Anyone ever go faster with less lift?

Anyone ever go faster after switching from 1.6 intake rockers to 1.5? I’m thinking velocity increase with less lift. Which is better, velocity or volume on intake flow?

More lift sometimes makes more power and sometimes it doesn't. Just depends what the engine needs.
https://www.motortrend.com/how-to/trying-find-extra-power-rocker-arm-testing/

Waht andy said, and I would add that you need to make sure you are still controlling the valve, if you add lift with a higher rocker ratio and lose control of the valve you will probably lose power.

If your talking SB I would always run the highest rocker ratio I can find to bring the pushrod up straighter (I know it's not much but it don't hurt) then match my cam to those rockers to get the valve action I want.

Read something awhile back, I think it was Joe Mondelo. You want no more lift than 15% of your bore diameter. My 511 has a bore of 4.375 and my lift with a 1.65 rocker puts it over 15% of the bore. My measured lift is .665 . The 15% rule would be .656. The optimal target is 12%, but not over 15%. I’m thinking with my victor head(which I think suffers from lack of enough velocity) may benefit with a 1.55 rocker instead. A 1.55 gives me .625 measured lift. Just a thought.

Personally I feel that you will see more of a change with changes to the valve timing events, rather than just lift itself. Using rocker arm ratio as an example, is the increase or decrease in lift making the power? Or is it the change of valve timing events and valve velocity showing the increase/decrease in power?

Billy Godbold has talked about a multiplication factor he uses for calculating valve lift.

He works on 0.45 - 0.48 of the intake valve. As an example 2.25" intake valve x 0.45 = 1.0125" of valve lift. On a Super Stock or Pro Stock style engine it sounds about right. You're probably not going to apply that factor to some of the engines we build.

The only way you'll know is test it

There are various formulas to get you in the ball park but you have to understand the assumptions used to create the formula before you know if you should use it or not. PipeMax will tell you how much lift you need for a certain combination to avoid choke. I always run the engines thru PipeMax before ordering parts. It is just a quick and easy way to double check my assumptions.

I give up

Thanks Andy. Appreciated the linc as well.

I agree and that is gonna happen first. I only mentioned the rocker ratios because of my victor max wedge heads. Most that have used them found them to be underperforming(RAMM). Dwayne told me they have a very large bowl on the intake, almost as big as the valve. I believe that huge bowl may be the reason. It could be causing the air to slow at the bowl allowing fuel to drop out of suspension. My thought was maybe a short ratio rocker arm would help keep the air/velocity thru the bowl with the shorter lift. Besides, I may have to switch from 1.65 to 1.55 to get more piston to valve cleanse anyway. I’m just try to get the p/v clearance without killing any power. A new cam on a 110 is my last resort.

There is a lot of info on this page I just came across. cylinderhead flow tech book

...and that theory was based on what?

So here is what I'm thinking:

1) assuming that a wedge head is used, and therefore for a particular valve diameter size increasing the lift brings the valve closer to the cylinder wall, therefore shrouding the valve

2) but #1 above is certainly going to be impacted by the valve angle in the head (which is why I said "wedge" b/c a hemi chamber would certainly not follow these rules quite as readily I'm thinking)

Not saying this theory has no merit to it, but I'd like to understand what criteria it is based on.

Anything more than 15% of the bore diameter in valve lift and turbulence is created off the back of the valve, which kills the velocity. With a 1.65 rocker I’m over 15%, plus I have a [censored] designed head. Thought it might be a win win for me. Plus I might gain a bit of p/v clearance too. So a win win win actually.

Never mind

I'm sure thats the whole deal. That valve too close to the cylinder wall will kill it. I think i will plan for the 1.55 rockers in place of the 1.65.

I've never reduced rocker ratio and gone faster, but I've added rocker ratio without seeing any gains.

[Have a nice day

Your right, I was thinking that wrong. The writer wrote that more than 15% of bore in lift created turbulence, killing velocity. I don’t know his theory.

That doesn't make any sense so I'd avoid following that theory. Race engines almost always have valve lift that is greater than 15% of the bore size. A 4.50 inch bore would be restricted to 0.680 lift which isn't enough for a big race engine. A big bracket engine will use lift somewhere in the 0.750 to 0.850 while a pro built engine will be up to an inch of lift.

That’s why I’m asking. Thought I would see if anyone else agrees with this.

I give up

Kaase is a very sharp guy.

Nope, I literally see it as the valve getting closer to the cylinder wall as the lift increases.

Yes, the starting angle is such that the valve intially starts on-center, but that very angle also has it moving towards the exterior cylinder wall. I mean theoretically if you kept on going it would simply run into the wall.

Having said that, I suspect that given the lift ranges most of us are talking about (street builds), so maybe .650-.700 at most (?), this probably does not hinder the air flow much.

Further on, I suspect that the shrouding due to valve diameter size has a much bigger role, especially the part of the valve head closest to the cylinder wall. This I believe is part of the reason why doing a de-shourding cut on the combustion chamber often helps with the flow.

I agree with Diplomat360 as I mock-up assembled my big block without pistons and rods to check the radial clearance of the valves and cylinder walls. I got the BIG suprise when at maximum lift I saw how close the exhaust valve was to the cylinder wall. I should have done it earlier, before all the final machine work.The clearance did reduce as the lift increased. I ended up with .030" radial clearance at max lift.No room for a bigger valve there. This dimension doesn't even take into account for any growth or deflexion due to heat or RPM. I really got lucky here. Engine is iron big block, 4.350", .690"lift solid roller w/Victor Max Wedge heads. More lift or smaller bore and there would be trouble.The point of the least clearance was in top ring territory, so no wall reliefs there. I'm sure that there is some valve shrouding effect here. The intake valve had, visually more radial clearance.I used a round wire gauge to accurately check the clearance. ( Miked a paper clip!) Bill

Are you happy with the performance of those heads? I use the same head. Are you still using the 2.200 valve? What compression?

I have not run the motor yet, due to some medical issues I had to take care of. It is 13.5 on compression, keeping the 2.20 valve. Didn't think there was good cost justification there with a 4.350" bore. I may have to use a very small amount of spray to hit my target for index racing and so the valve upgrade would be not too far from the nitrous cost I may need anyway. I'm sure ,dollar for dollar, spray is the better way! Bill

Y'all are following the trail that leads to relocating the cylinder heads farther inboard to get the open valves away from the exhaust-side of the cylinder walls. If link below works, it'll take you to a pic of a head that Jesse Robinson ("RAMM") modified for an older EMC event to offset the head... looks like about .100" to me, FWIW. This is one of those things where other engines (non-Mopar) can have an advantage cuz their heads have the valves located closer to the center of the bore. IIRC, it's one of the revisions that B1 heads (not B1-BS) have compared to the OEM architecture. PICTURE

Thanks for the great article showcasing some remarkable talent. There's always a way to get something done, but some people have a budget and not a bank. I'm one. Just another old retired guy building hot rods. The author of this thread may be in the same catagory. I looked diligently back thru the Edelbrock Victor info sheets and there it was. Check piston to valve clearance AND valve to cylinder bore clearances. I missed it. My fault. No funds to go back on it now as I can skate by on this one,w/ .030" radial clearance.Luckily, I opted to include nitrous oriented clearances and top rings to accomodate safely a small amount of spray in my build. I have to "run what I brung" at this point. I would not build another engine again to make more power w/Victor heads.Lesson learned. Bill

As a point of interest, a 2.30 intake valve will hit a 4.375 bore at a little over .800" lift.

Yes, I agree. I would never purchase these heads again. Jesse offered to fix mine for about $4000 a few years ago. I would rather buy new heads. Thanks for the pics Brad.

Didn’t know that was a problem on these heads and why a larger ratio rocker didn’t get you anything. Impeding flow is not a good thing and kills velocity.

They’re not any different in that regard than any other heads that retain the stock valve placement and angle....... in other words......”most” of them.

Ok, I understood they were in a different location from standard. Got it.

Nobody cares

Doesn't surprise me, 2.30 valve is pretty big and 4.375 is kind of small for an engine that needs a 2.30 valve. Typically you would want a 4.500 bore for that big of a valve. It might not pay to put a 2.300 valve in a head if the bore size is only 4.375.

Since we are talking points of interest. We run a 2.300 intake valve in a 4.25" bore in the Vette. Non wedge of course. But NONE of this math works in that situation save one persons source Oh yeah a lot more lift than the OP's source sites as well, a LOT more.

Upon my discovery I came to the same conclusion. I also learned that stock valve spacing limits you to I/E valve sizes of 2.250/1.81 or 2.30/1.78. Not enough radial clearance for 2.30 and a 1.81. Nothing super technical in that experiment, just mocking up parts on hand.

This is for my -1 tunnel ram 511 with a little over .800 lift.

That was my point: facts matter less than "how you feel about it"

umm...sort of a strange "turn" to this thread...and I'm not quite following the under-current since the most recent remarks seems to WANT to say "I disagree" but they just can't seen to get to actually making that point! lol

@polyspheric: I replied to your commentary re: my assertion the valves actually open towards the cyliner bore as opposed to the center, I even included a Mopar small block cut-through...I see that your original post, to which I responded, has now been editted by you, and is gone and has been replaced be a rather terse "Never mind"???

So the whining and complaining from @GTS340 and '@Harry's Taxi 2' is exctly what?

I mean, does that actually contribute anything to this discussion???

If any of you have an answer, ney, even an opinion based on supporting evidence as to what '@mopar dave' original post is about, I would love to read about it.

[now where is that "shaking my head with disbelief" icon]

I agree with Diplomat360 as you can just feel the tension in this thread,as in several others lately. The point of the original writer is getting lost. It is very hard to convey points effectively and in a timely fashion as compared to a verbal discussion.Most of us are here because we want to run that personally favored engine/vehicle combo and not particularly because it makes more sense.Running a big block Moparis truly not the best choice if your looking just to go fast. Much better alternatives out there. Especially if finances are a big concern. I underststand where Mopar Dave is because I too chose the Victor heads. They are basically great heads for that easy to build 700hp big block Andy describes in his book. The early hype that surrounded suggested something different. I bit and others did too. So many issues if you want to go past 675-700hp. Spent several hours talking with member Jeremiah on this subject as well.I know Mopar Dave is just trying to wring of few more hp out of his combo.To get large gains at this point would be large money and large work, but we need guys like Dave to post their projects and pass on their findings to the rest of us. I am very appreciative of this. I know there would be more of us that could push the horsepower needle of the dyno past 700hp with a big block Mopar (NA), but you need resources and money. I don't believe that is indicative of the majority of members /readers here, so we need to be a little more in tune to that. I sure don't feel my arm being squeezed to read or respond to anything here that I may come across. No one has to do that. It's America, Land of the free, Home of the Respectful. Off my stump now, Bill.

So agreeing with someone pointing out a non-contributor to a thread is now considered "whining and complaining"? Have you not noticed all the non-contribution, snide remarks over the years from polyspheric?

Also, i looked back and i can't seem to find where only Diplomat 360 was made the remark Tsar.

Most forums have become technically useless over the years due to the "I'm better, smarter and have a bigger piston than you" mentality. and that has led to those with actual knowledge and experience to leave.

I don't really see any problem in this thread. Dave got some bad advice, or at least confusing advice, about valve lift and power so he asked a question. He got a pretty clear answer that less lift isn't going to make more power. He also was told that more lift may or may not make more power. Basically the answer in this thread is the same answer to most questions on this board, "try it and find out". Engines are complicated and nobody knows what will happen on any particular engine when some part of the combination is changed. Guys that spend a lot of time in a dyno cell or at the track are constantly getting surprised about what works and what doesn't work. On Dave's engine I can guarantee that less lift isn't going to make more power. My guess is that more lift might make a small amount of power but I doubt it would be worth the expense of new rocker arms and springs.

Harry's Taxi 2:


LOL, alright, I'll be the first one to say "sorry", but in this case I honestly don't even know what I should be appologizing for.

I only spotted your remark of "thumbs up" to GTS340's "...nobody cares..." remark, and I genuinely thought that we, as a group, can do a LOT better than to 'feed the troll' (as that appears to be the point that you are making about poly's previous contributions). In comparison, if you recall, my response to him was an actual diagram of the head and valve positioning in the chamber in relation to the cylinder block itself.

So be it, although I do not know people's history on these forums, and truthfully consider myself to be more of an outlier given my "affair" with M-body mopars!!!...therefore my interest most often lies in understanding the tech/science behind the issues and/or challenges we face while wrenching away on our rides.

...and NO, no one made me the "remark Tsar", I have no interest in that role, and much less so in that type of content...but if my comment did come across as such: you sir have my appolgy for that!

Apology very much accepted. I sometimes fail to realize typing doesn't always convey the intended message.

Really appreciate all the replys on this thread guys. I did learn from it. When i originally posted it, I thought that the valve did get closer to the cylinder wall as it opened, But thought it was the lifter side. So there is something learned here anyway and yes it looks like there is a loss in hp with reduced valve lift in my circumstance. The simulators show about 4hp loss going from 1.6 ratio to 1.5. Something Harland Sharp told me the other day, When checking rocker ratio with checking springs, the ratio may be as close to 1 full ratio higher, but when you install your heavy springs, it brings it back to or close to the advertised ratio.

....and then back up to theoretical max as/if it approaches loft.

Before some of you were born, almost every BBS had... (wait for it): rules.
One rule was "personal attacks on an author, without other content, result in banishment".

That would remove at least 20 people from this board.

The primary restraint against bad behavior is manners, sadly absent here.
Rules are for the discipline of those who have none, but misbehave.

What is a BBS?

Bulletin Board System...ahhh, good ol' days, when one enjoyed the modem's speaker crackle away as the connection to the "outside" world was initiated!!!

Short Version: the precursor to today's forums, such as our little home right here. BBS'es were often ran on invididual computers that folks would have running in their basements (I did), where the caller's modem would connect to your specific BBS number. Of course, some BBS'es were also hosted on bigger servers, especially as the amount of folks using their modem to connect to the Internet rapidly increased.

I'll throw in my unsolicited 2 cents.

I don't know polyspherics background but I get the impression he has a lot of experience and responds with a lot of good info.

Also would say, (and just my opinion) that he writes in a way that some people may find hard to understand without the same experience/background. (as in, great info but may mean absolutely nothing to people with no context/reference)

He then gets annoyed, as it seems most are dismissive, but from my perspective it would be received better with more explanation?

Completely open to the possibility of being entirely wrong here, but would say there have been many times I've searched a subject to see polyspherics edited posts saying "never mind" , etc, or essentially deleted and thinking..... I would really would have preferred to read his first comment.

So polyspheric, of course you are free to do as you please but again, I think what you may perceive as dismissive may be hard to understand by some without more explanation. That being said I think your efforts would best be left as originally intended than deleted but that's just my opinion.

This post and comments make me think of Mark Levin , PHD, the radio talk show host who write books that are way to wordy and way to long on making his points, so bad I can't read them.
Me thinks he is writing in that style to impress other PHD

When he posts something that he later realizes was incorrect or when he posts something that he is proud of and it doesn't receive the praise and worship that he is looking for he pouts and changes his posts to "never mind" or "have a nice day"
While his posts may sometimes contain information of value, it rarely seems relevant or beneficial to the thread and is almost always posted in a manner that screams "I'm smarter than you"

When he posts something that he later realizes was incorrect

Some of my work: http://victorylibrary.com/mopar/mopar-tech.htm
Find some mistakes.

Thought you gave up?

glad i don't get offended easily.
i'm old, and have been called everything in the book, except the "new", computer based, put downs.
i don't know what they mean, so fire away ! i just figure it's what i have been called in the past, only this time, it's the modern, present day interpretation of past descriptions.
it will take a lot to make me leave, but over the years, there has been MUCH knowledge lost from those that know, just because they got fed up with the constant barrage of snide remarks.
that's too bad. that knowledge would serve younger members well.
my old noggin is filled with cobwebs, and is slowly being overtaken with spiders, but i will continue to offer what i know works, and also continue to ask questions to refresh what the spiders have eaten up.

Can't we all just get along?

This is the part of Moparts I didn't miss while I was "on vacation" for almost 2 years. I've had a few with people here over the years (including at least one person on this thread), but it's not worth the oxygen now to bother. And that's coming from someone who is quick to admit I'm a "slow learner" about these things.

Must be cold back east Winter is silly season afterall

Indeed

Apparently not today.
Tomorrow don't look so good either............

Its just the annual Moparts roast of Polyspheric - The start of race season will be here in six weeks!

It's a natural occurrence.
When enough ill-mannered people find their comic-book knowledge corrected by someone they don't like, their only recourse is personal insults.
Helpful hint: in the most amazing coincidence, pointing out where I'm wrong is almost always: they didn't understand what I wrote.
Find my comments on Barton's hemi rockers. AFAIK not one person saw what I pointed out: Barton's geo is not perfect, the question was "is it enough to be important"?
[carrier wave]

Considering this topic has spread like the bottom of a fat lady taking a seat, i will expound on my infinate wisdom, or lack there of.
#1. We don't know what we don't know. It seems we know even less when we challenge others.
#2 No rule is ever perfect.
With these thoughts in mind , i offer the following.
The best we can come up with are trends, because it seems there are always exceptions.
Case in point; i was told by someone from Indy cyl heads to NOT run over .825 intake lift with -385cnc-13 heads. Ok, why? Something about the flow goes negative at about that point? (Can't remember the reason)
So my cam with .868 lift would be wrong, correct? Maybe, i don't know. They base thier comment on 350 motors built with those heads. Maybe they are right,,,,,,BUT, nobody has infinately tested all the possible changes to all the possible combinations, including porting, bore size,add infinitum. And that cam made VERY good power in my 550 inch 440-1 motor. So, i keep looking for trends, from lots of sources.
And finally, to ALL, have a nice day, and thanks for your input 🤕😁

nobody has infinately tested all the possible changes to all the possible combinations
This^^^!

IMHO one of the most important errors in reporting test results, few even mention "We have not the time or resources to explore all possible variants of spark, jetting, spacer height, ICL, etc. which may have provided even better information. What you just read is not really instructions to be followed, but a trend which may prove useful on your project".

well, Cab always says : "test, test, and test some more ! that's the only way you will know for sure !"
i can't dispute that statement. unless you do as he says, you won't know.

I recently viewed a David Vizard video where he stated the flow in the port will go negative because the lift takes away from the short side flow after the flow gets to much in the other side of the port.

So, less lift might be beneficial? Looks like I will have to go to a 1.5 rocker on the intake side if I want to use this cam. I have been contemplating new ported -1 heads with a matched cam.

I have worked in research for almost 10 years now. Some of the adademic staff I work with will postulate over theories for an eternity. Others will give it some thought and we will conduct a series of experiments and we will reevalutate from there. Point being, the later gets more meaningful work done.

Test the 1.5:1 rockers and evaluate the results. The reality is it may make little difference to your performance, but you'll learn something along the way.

Some info for your situation; my results;;;;
550 cu in, 15/1 compression, methanol injection using a Terminater tb. 440-1 heads with 2.30 int, 1.78 ex.
Fully ported by RJ in Iowa, flow numbers were hi from one source(399 at . 800) less stellar from another(370?) Cam- Jones inverse flank roller , standard size core. .868 gross lift intake, .816 ex, lash ,. 019 int, .020 ex. Duration is 284/296/114 . Intake is a 3X. 2 1/4 dyno headers.
Best pull was 926 hp at 7200 rpm. Power still climbing , but not much (1 or 1.5 hp per 200 rpm?)
By my tests, looks like these heads like lift. But then, only three cams have ever been tried. Each one bigger, but other mods to the shortblock.

Yes, and i think most do. The -1 head has always been a great head. The E Victor, not so much. Jesse told me best thing for this head was angle milling. Brad said he gained nothing going from 1.5 to 1.6 and he uses the same heads as me. Would had same result going from 1.6 to 1.5. I have no choice now but to put a 1.5 intake rocker on it as there is not enough v/p clearance for a 1.6, so if im comfortable with .050 on intake and .080 on exhaust i run it, if not a new cam is my next step. The cam can only be degree'd at 106, either way from that there is not enough clearance its that close.

In your case the question is moot since you're going to have to use certain parts for the engine to work properly. It will be what it is.

Yes and I hate doing that as I feel I may be leaving power on the table. That is the reason I mentioned new ported -1 heads with a matched cam for the combo. I’m sure it would make more power, but would it make enough more to make it worth all the extra expense? I’m thinking another $5000-6000.

If you had some new -1 heads, and milled them down to the same chamber volume as your current heads..... who’s to say you’d have any more V/P clearance than you have now?



Brad has std port Victors........ and no rockers were swapped during the dyno session.
It had 1.6’s on it.

Yes, that is the reasoning on new heads. Only take off enough to get 12:1 and gain a little clearance there. What are the chambers on a -1 head in cc? I think I had .035 taken off my victors to get 12.5:1. I’m not sure of Brads circumstance, but I assumed his testing was at the track.

Vizard has stated pretty specifically that flow during OL is far more important than suspected previously.

When heads are flowed, is that with a 12.0:1 CR domed piston below the (partially open) valves?
At full lift, there is almost no intake vacuum, while (assuming a good exhaust) at OL vacuum from the return pulse may be 7".

Flow bench: useful
Dyno: more useful
LSR: most useful

Since Brads Victor combo hasn’t yet run in the car, the track testing he did would have been with the old combo, which used std port stage 6’s.

Andy’s rocker test proved you only need what you need, and that there isn’t always going to be any magic with a rocker swap....... since he basically saw no gains by increasing the RR in that test.

My friends old 13:1 Pontiac bracket motor lost a solid 15hp by swapping the intake rockers from 1.5 to 1.6(.556 to .593 lift).
Played with lash, timing, jetting, spacers...... no improvement.
Put the 1.5’s back on...... poof...... 15hp came back.
The next year we replaced the SFT cam for a .596” solid roller....... and picked up 50hp.

I have read a bunch of David’s writings. Sharp guy for sure. We all know the answer to the flow bench . My app has dish pistons and 78* of overlap.

Sorry for any confusion; yes, my rocker ratio tests were pre-Victor heads. Thx

No gains at the track, but there were some gains on the dyno as I recall? 5-10hp??

It was with my old ported '452' OEM heads, where I went from 1.5s I&E to 1.6s I&E and saw zip / nada / zilch show up at the track. I was really expecting some improvement, but... nope. It's not apples to apples, but it's at least one experience where more ratio got me nuttin'.

Intake-only 1.6s did show something like 5 HP w/ the Stage VIs on the dyno, but I ended up sticking with 1.5s on both I&E once the engine went into the car. The 1.5s went with the Stage VIs when they were sold.

When buying new rockers for the Victors, I went w/ 1.6s to go along with the switch to a solid roller. Fully loaded against a "real" spring they're 1.54-1.55 with a net (after lash) lift of ~ .650" w/ the RX roller.

Which brand rockers Brad? Got to say Dwayne is real close or spot on with the clearances he listed with retarding my cam per degrees. I over shot the 106 install degree and landed on 108. At 108 I measured .054 and .065 on intake and exhaust with .020 lash in each. I still have a 1.6/1.5 rocker combo. My math tells me it will be very close on both valves at 106. I’m sure it will take the 1.5 on the intake to get to an acceptable clearance. Hope to get more time this weekend.

I've used a number of different rocker brands and types. IIRC, the all 1.5s vs all 1.6s test used Rocker Arm Specialists 1.5 stainless-steel rollers and Crane "Gold" 1.6 aluminum.

The Stage VIs used Hughes (formerly Probe Industries) standard-offset 1.5 and 1.6 rockers.

The Victors have Hughes Victor-specific intake & standard exhaust 1.6 rockers.

The only ones I have pics of are the rockers on the Victors. The exhausts are their current "channeled" standard-offset style, while the intakes are their earlier "full body" .600"-offset style.

Ok, thanks for posting.

I wonder why you are having clearance issues? I run a lot more lift and don't have any clearance issues. 268@.050 exhaust is 27x @.050. .465 lobe with 1.6 rockers. With the victor heads you will want to run as much lift as possible.Have you considered cutting the valve reliefs deeper? https://www.lindytools.com/ihpc

On 440 -1 heads. They start life at 75cc?, Max stated cut is down to 62cc. But as Dwayne pointed out to me, work on the heads can alter how much would have to come off to get to 62cc. In my case it ended up being too much for high (15/1) compression, and i had to have a head welded and fixed. Now i have what i consider to be the ultimate set of moderate compression heads! Someday maybe on a BIG pumpgas street motor😁
So if you plan on buying new 440-1 heads, mike the deck thickness, and only cut them half of what it would take to get to 62cc. I think that would be . 040. Now you have a set of heads that can survive refinishing the decks more than once. At a multiple of cuts totaling . 080, they might not like super high compression or heavy doses of nitrous.

I would have to check my notes, but I thought I had .035 cut from the head and I used a .042 head gasket in place of the old .052. I use icon pistons. Evidently they don’t have deep notches. Something else odd I found while decreeing cam, when I installed straight up, dot to dot, the exhaust valve ran right into the piston. It did not do that at any other point , A4, A2 or R4.

You need deeper valve reliefs.You may be lift limited regardless of cylinder head choice.What is your current combo? Weight, gear, cubic inch, converter, et, mph etc. I know you and others have not been happy with the Victor heads. My father in law and I have had the opposite. His has been an over achiever from day 1.

Just checked my notes and i had .045 taken off heads. Chambers are now 67cc. Icon pistons have a 12cc dish. Its a 511 with 12.5:1 static. Heads are cnc ported with an intake port size of 330cc. They flow 278@.400 and 356@.700 intake and 203@.400 and 254@.700 exhaust. 2" headers with 3.5 short exhaust. 727/8" 5400 flash, foot brake, 4.10/28" tire 3480# race weight. I currently run a Indy T ram, but previously ran a 1100 Dominator which ran a best at that time of 10.06@134.

Just found the piston specs. Valve notches are .215/2.30 intake and .199/1.88 on exhaust. Pistons have .002 positive deck.

Just my thinking on the subject. Look at the total flow sheet find out where the max flow is then use a lift of .050 more.

And if your not going to do that, then an extra .030 or .040 lift from a 1.6 I don't think amounts to anything at the track.

And max lift has nothing to do with p/v clearance. They are closest at opening/closing points Valve timing (duration/centerlining) is the key player here. I am also surprised you are having this much trouble with 269 degrees.

I have been using a 1.6 on the intake only. I now do not have the clearance, so a 1.5 is in order, but was curious to any real performance loss doing that. Head max flow is at .700. With a 1.6 rocker my true lift with 1243 springs and lashed .020 is .665 and with a 1.5 will be .625.

I would love to see what would happen if you put an Isky RR735 rollercam in it. The cam is 278/288/110 . Intake lift is . 735 with a 1.5 rocker, lash was(?) .026 . .200 diration was close to 200 on intake, but it needs good valve springs. Not sure how much overkill i had, but i used Comp 947 tripples at 330 on the seat. Up the compression somehow to as much as you can run, and mid nines at 3500 lbs could happen. That cam was making 800 hp by 5700 rpm in a 4.5 bore 528 at 13.5 compression and peaked at 847 at 6900. I was using 1.55 Jesel rockers and . 043 rings, which from what i understand make a difference . But i like the power curve on that cam. It didn't seem to want more converter than about 5200 to 5600.

There wouldn’t be enough clearance for that cam. My old flat tappet 270/276-110 had .118 on the intake and .140 I think on the exhaust. I am a bit surprised this mild roller swallowed up all the clearances. That solid flat tappet was installed at 105.5.

Was that .118/.140 figure measured before or after the heads were milled.045”?

Your old SFT lobe vs a moderately fast SR lobe of the same duration @.050”.......... the SR would only have about .015” more lobe lift at TDC with both installed at 106.

With the new cam installed at 106, what is the lobe lift at TDC?

The roller lobe I was using for comparison would be .154”

Here’s a dumb question.........
You’re not trying to degree the new cam and check for clearances with a flat faced lifter, are you?

The .118 measure was after decking the heads and using a .042 gasket. My lobe lift is .430 giving me .665 with .020 lash on a 1.6 rocker at max open. Yes I am using roller lifters for measuring. I still have not ordered new pushrods yet, so I have been using the old flat tappet pushrods to measure. They are 9” long, too long as I have the adjusters almost all the way out to fit for measuring. Does this upset the measure at all?

I think you may have found part of your issue with the longer lever by about .150 to .200".

the adjusters almost all the way out
reduces the ratio slightly

I haven’t measured yet, but I think it’s gonna take a pushrod about .250 shorter.

Depends upon the brand / design of the rocker. You can't say either way without having measured the lift curve with the adjusters at max and min extensions. Yes, I have data to validate my statement.

If the adjuster is parallel to the pushrod axis it always does, by extended the length of the pushrod lever.
I have the trigonometry.

A bigger rocker ratio is also a test of "Is my cam close to being too much for my displacement, static CR, ICL, LSA?".
Less power says: could be.

Since you insist on... well, just being you, I suppose:
- You made a blanket statement: "the adjusters almost all the way out reduces the ratio slightly"
- I responded that it depends upon the rocker, etc. I have data that shows it both ways, depending upon the rocker geometry.
- You said "I have the trigonometry".
- I have the CAD files that validate my baseline measurements within .002-.003". No doubt they factor in the trigonometry, as well.

So, you have basically zero threads(or less) showing below the rocker now(pushrod cup almost touching rocker body).

The adjuster being screwed up in to the rocker body further generally increases the ratio(slightly).

For first diagram, the "A" measurements are with the pushrod adjuster extended about .100" beyond where they should have been. The "B" test is w/ the adjuster length shortened to it's min acceptable length:

Lift --- _A_ --- _B_
.010 --- 316.5 - 315
.020 --- 305 --- 303.5
.050 --- 281 --- 279.5
.100 --- 255 --- 253.5
.150 --- 235.5 - 234
.200 --- 218.5 - 217
.250 --- 203 --- 202.5
.300 --- 189 --- 187.5
.350 --- 175 --- 173
.400 --- 159.5 - 158
.450 --- 145 --- 143
.500 --- 127.5 - 126
.550 --- 109.5 - 107.5
.600 --- 87 ---- 85
.650 --- 56 ---- 53.5

Lift -- .685" - .682"

The second diagram represents the config for the "C" (long adjuster) and "D" (short adjuster) measurements:

Lift --- _C_ --- _D_
.010 --- 314.5 - 315.5
.020 --- 303 --- 303.5
.050 --- 279 --- 279
.100 --- 253 --- 253
.150 --- 232.5 - 233.5
.200 --- 216 --- 216
.250 --- 200 --- 200.5
.300 --- 185.5 - 185.5
.350 --- 170 --- 170
.400 --- 155 --- 155.5
.450 --- 139 --- 140
.500 --- 121 --- 123
.550 --- 101 --- 103
.600 --- 76 ---- 79
.650 --- 35.5 -- 42.5

Lift -- .663" - .670"

============================================

Yes, if I remember correctly it’s 1 full turn from bottoming the cup at the bottom of the rocker. I just got a new pushrod checker. I will try it with a checking spring and see what I get for a measure on intake valve this weekend.

Ok, looks like it’s only .003 max different in the area I’m checking which is just off the base circle.

Hmmmm... seems I forgot what I had said not that long ago. I'm going to do my best to stay outta these petty and just go on about my business.

Maybe I just don't see it, but where are the alternate pushrod positions in the rocker indicating adjuster length?

I will have to look at this on my pc, but looks like shorter pushrod creates more lift.

IMO, using pushrod length to affect lift is a bad idea. You have a limited range of correct adjuster position. IMO the adjuster (if you are using a cup adjuster) should be as far into the rocker as it can be. If you are using a ball adjuster (depending on who made the rocker) it needs to be out 9/32 minus .050 plus zero.

A = ball-type adjuster w/ 9.200" EL (effective length) pushrod
B = cup-style adjuster w/ 9.575 OAL (overall length) pushrod
C = ball-type adjuster; pushrod 9.425" EL
D = cup-style adjuster; pushrod 9.800" OAL

^^^ - Each style (ball vs cup) has a "sweet spot" where it's supposed to be set. Jacking around w/ their positions for the sake of tweaking the lift curve isn't a great idea... IMO.

Changing pushrod length to correct clearances was not my intension. You see, the pushrods im using to check my clearances are too long because i switched to a solid roller from a flat tappet and thought i could just use my old pushrods to get my measures for now. My current pr measure 9 1/6" long. I need 9" to maybe 8 15/16", so my old ones are not too long to get my measures after all. I have 1 thread showing on adjuster under rocker with lash using 9"pr.

I found some notes I made.
My original description of the adjuster as parallel to the pushrod may be true, but it's not significant.

The shape in question is a right triangle. The geo:
The adjuster thread is 90 degrees to the pushrod lever, a horizontal line equal to the lever's length (the triangle height).
The exposed thread is a vertical line descending from the left edge of this line, the height is the difference (the triangle base) in adjuster positions.
Draw the hypotenuse. It's longer than the 1st line. In any right triangle the hypotenuse is always the longest distance.
Therefore, the pushrod lever becomes longer as the thread length increases.
The valve lever length is unchanged, so the rocker arm ratio goes down.

If the pushrod lever (triangle height) is 1.00" (fairly common) and the valve lever is 1.70", the ratio is 1.7:1
If the exposed thread distance (triangle base) is increased by .100", the hypotenuse length is the square root of the sum of the squares of the 2 sides (Pythagoras).
1.00^2 + .100^2 = 1.01^.5
1.01^.5 = 1.005

The new ratio is 1.70" ÷ 1.005" = 1.691:1

If the adjuster angle is different, the math will be off, how much and in which direction? Give me the angle.

I was taught to watch rocker arm tip on the valve stem and shoot for having that contact to start on the inner third of the stem when closed and go across the center to the outer third at max lift
That has worked for me really well, especially on Mopar single shaft rocker arms

I was never good with that kind of math, but i did set up my pushrod checker yesterday to 9" which gave me 1 thread out the bottom of the rocker and my intake valve clearances were less. I did not write anything down and thought maybe my dial indicator was not quite the same position as when i measured with the 9 1/16 long pushrod. I discounted my figures and moved on because those results were opposite of what i thought they should be. That is interesting and worth noting.

I thought my wear patter looked good with the 9 1/16 pushrod and flat tappet.

Changing pushrod length won't effect that.

To answer your original question, i did go alot faster with less lift with a 360 and iron heads.

http://victorylibrary.com/mopar/mpcam-tech-c.htm
Well junior, all these specs are wrong. But when you just compile other people's info instead of taking actual measurements I understand.
You also had the bore spacing for the modern hemi listed incorrectly for a good bit. But let me guess, just a typo??

I'm interested too.
More specifically on the exhaust side.
The exhaust lobe/lifter/pushrod has to open the exhaust valve against both cylinder pressure (times valve head area) and the valve spring pressure all multiplied by the rocker ratio.
The additional exhaust airflow at high lift may not be worth all the extra valve train strain and losses. The exhaust is going to exit under much higher pressure, and overlap is at low lifts defined by duration and LSA.
The Intake opens into an evacuated chamber, and only has atmospheric pressure to push air into the chamber (NA).
Many race heads will use smaller exhaust valves so a larger intake can be installed. Larger intake has more curtain area (area for overlap and flow), where the smaller exhaust valve takes less pressure to open against the post ignition cylinder pressure.