Race Engine reality, what works

So lets talk about what works. What building parameters or "tricks" actually made your car go quicker. Lets limit this discussion to engine build options. Machining , accuracy of clearance, ratios, weights. Did that trick hone job pick you up? Straightening the lifter bores. Perfect piston ring grooves? Dead on rocker geometry? Every valve spring the exact same pressure? Bearing clearance to the .000X? Thin/light ring pack? Rod ratio. Light weight components? All this stuff is that it gets debated often in different discussions. Not talking about comparing to poor sloppy machining. More of good average stuff vs the best. My experience is if the above areas are decent the amount of improvement is next to nothing. My current motor went from .043" rings to .9mm, ran exactly the same. Then a new crank. It was 5lbs lighter. Ran exactly the same. Looking for real world track results.
Doug

Great topic Doug! Might I suggest that the topic applies to somewhat current builds within the last few years?

LOL. Most guys don't test correctly.

Most guys don't dyno stuff B2B where you take out many variables.

Most guys have a chassis that is already at its saturation point for power. Any more and it just flexes away any added power.

The biggest changes I’ve seen usually revolve around some component that’s either not working right, or isn’t a good match for the rest of the combo.

The biggest differences I’ve seen have come from these items....... but not at all consistently.
For each instance where I saw a big change....... there would be dozens where it did nothing.

- cams
- carbs
- intake manifolds
- swapping to a tunnel ram
- vacuum pumps
- headers

Years ago, sealing the carb to the hood. This was worth 1-3mph and +.1 in ET....Nobody believes me on that, but it is true.

For me this 2019, it was upgraded rocker arms and push rods....Was wrecking pushrods and rockers like candy at .680 lift with our new 400/512 combo. Went to Comp SS rockers with more offset on the intakes, and Manton series 5 extreme push rods....Wow...Night and day difference. Never even took the valve covers off this year.

Was using the 440source rockers and pushrods, which worked well for 6 years, but now we are in the low 6's in the 1/8th and finding we needed better parts.

Also, the other biggest gain we netted was working with Thumper on the carb setup and I ported the crap out of the manifold....netted .22 total and 2mph

Last years big gain was calling Hoosier and getting the right slicks for our car....How about a 1.31 60ft!

A while before that, sealed the carb to the hood.....

Things that netted us nothing, but we like anyways:
Firecore wires over Procomp generic ones
Light weight crank....6lbs lighter
Switching from a 440/512 to 400/512
increasing compression from 10.75 to 13
Front facing hood scoop
Trans brake
PPP shifter
Magnefuel 500 pump over a 275

This most likely falls outside of the original topic, but there is no single more important part to having a fast car, than the torque converter.

It is definitely not outside the topic.....Many combos are held back by the wrong or bad torque convertor. This is especially critical to the folks that run a glide....Typically you know when you have the right convertor, but not so the other way around.

Lots of guys like me to spend big money for little gain. Again 95% of us are bracket racers or street n strip guys so thin ring packs, lightweight components, belt drives, and vacuum pumps show little gains. A 5.00 lock ring on your distributor works wonders and is surely cheaper than other options out there. As far as deck plates I personally don’t use them. How long does a dead prefectly machined block in the machine shop stay perfect when the crank is bolted in place with 8 rods and spinning 7200 rpm. Now throw in the “heat factor). What does the block do when at Racing temps. Do you think it stays perfect like in the machine shop. Your guess is as good as mine but I’m thinking no. I like spending around 1000.00 to machine a block and balance an assembly at a shop I trust rather than crazy money making the shop owner rich. If it makes you sleep better at night then go ahead and spend big money. If you are sitting at home because you can’t afford the tricks, maybe it’s time to stop believing the ragazines written by guys that get paid to suggest you spend your hard earned money.

Doug, for me what I have found out going with better parts was longevity of the combination. It didn't necessarily pick up many horsepower or run a better number at the strip. However I had less failures.

Now regarding machine work I've always tried to pick shops that have a quality reputation. The reason being same point as above. Quality machine work and parts tends to make a combination last longer. I'm a bracket racer I'm not trying to gain every 10,000th of a second I want a quality combination that is consistent. Yes even good parts fail and good shops make mistakes but over the past 40 years I found that when doing this I spend less time working on my combination.

To be Honest the 512 Low deck I built makes about 150 HP MORE than I really thought it would make, Hrdro roller, dingleberry hone job, 440 source heads ported by me using a toy flow bench [Super Flow 110 ] ,wide ring gap on second ring, 9.7 to one compression, most of the ? in dvw's thread is more about longevity of the build IMOP. all that said ,, I love my Dodge Sorry Im sharing in the race section, my junk is Street & sometimes strip. The LARGEST gain I have done was from tuning, also getting rid of a baffled muffler & going to a straight through muffin

one thing I did to my stock block stroker that makes it live & gives me piece of mind as I race it, is bushing the lifter bores. Oil pressure is now always good where as before, once it got hot, the pressure at idle was almost nothing. I used a diy lifter bore bushing kit & honestly, when youre doing rounds & hot lapping it, oil pressure no lower that 25psi at idle keeps me smiling with a solid roller cam.

What didn't gain me much if anything was removing my 12.5:1 340 and installing a fresh 10.5:1 408 with W2's. It was seat of the pants only, but that 340 sure felt quicker than that stroker in the early days of it. converting from SS springs to caltracs, switching 4.10 gear for a 4.30 gear with a loose vert. and replacing my 950 holley for a 1100 Dominator when i had a small block. I never made any big gains with one component change. It was a bunch of small gains that worked in the end. Switching from a 10" 3500 vert to a 8"5200 vert made a gain. Switching to Hoosier QTP from the old M/T drag radials made a gain. I now use the M/T ET street R and its better than the Hoosier QTP. Installing a crank trigger made the timing rock solid, so it was a gain in accurate timing. I don't remember seeing any gain at the track, but accurate steady timing is always a plus.

I hope to see what adding over 2 points of compression does this year going from flat tops to dome pistons. I run alcohol so it’s no added cost to try it and the deal on the Pistons was to good to turn down. My last Edelbrock headed 408 ran 9.70’s so I’m looking forward to the results

I was surprised to see Dragula found nothing in a 2.25 point increase in compression. I increased mine 1.5 points. Hope I gain something, but will see.

I strongly second this one.

I have a lighter Molnar rotating assembly (mainly rods, crank weight was the same) and metric pistons rings. I did it mainly because other parts were close to the same $ and it has to be easier on the block.

Again, street/strip brigade here.

Same here, even for a dual purpose car. Went from too tight to too loose to just right to finally improve the 60-ft and reign in the slippage on the big end. The difference between the last two converters was .2 and 2 MPH, all the result of reduced slippage.

Getting a carburetor that's "happy" with the rest of the combination has shown solid improvements, too. Doesn't have to be any bigger or make more HP if you can improve the shift recovery.

Best bang for the buck is Take Weight out of the car, followed by take more weight out of the car, and finally remove weight from the car......

Biggest gain for me was cylinder heads .
From hand prepped out of box , to CNC (stock port) to current TF270
This was tried on my 440 and 505 RB motors . Solid .25 gain with TF270 over CNC source . Which is about what i expected .
This is from engine only , converter also made gains seperatelly .


Tex

biggest improvement I've seen is when I went from a 414(360)stock block 230indy cnc heads 10.5compression 630/270@50 cam in the dart it ran10.40s .everything else being the same I built a 436R3 short 13.5comp and 700/276-280@50 cam and ran 9.7s consistent.2points in comp little more cam better block rotating etc picked it up quite a bit.

Which motor, SB,BB or Hemiroid
Tuning and air flow has made the best improvements on my motors
No two men are equal, same thing on race parts

What I know works: less weight, more compression, make the engine as big as you can. So I started out with making my car as light as I could while maintaining the look I wanted. 3350 with me ready to race. Then it got a 15-1 572. The 5th full pass the car ran 9.3x. Since that time (630 passes) it has had engine maintenance parts. But still has the same heads, compression, cam,& rockers, headers, carbs and intake. Learned what lives and what doesn't. Pac valve springs, Isky bushed lifters, Landrum rear coil springs, Molnar crank, US gear pro gear have fixed any problems that have occured. Maintenance is very low. Same type tires (M/T 10.5Wx31) and overall weight. Swapped rear gear from 4.10 to 4.30 no real change. Aluminum high drum replaced a billet steel unit along with lightening the sun shell. This was worth nearly a 7lb reduction. It was also worth close to .10 in the 1/8th. Various converters picked up .20 putting the car in the 9.0x range. Shocks and springs have helped consistency but really haven't made the personal best any better (1.25, 5.72@121, 9.00@150). Though they sure have helped to put the car in the winners circle. In ways I'm a lazy tuner. Never really chased jetting, lash, timing. We've moved it a little with no real improvement. However nearly every trip to the track for us is a race. Our testing is usally limited to put the car on index or adjust for poor track conditions. We are focused on that. Cant win with a car that won't repeat.
Doug

I will totally agree with the converter. couple times I did things that I knew should have picked up the car, but it was like it had a governor on it,. changed the converter and boom several tenths improvement. And I will also say that while I always give all the info asked to the converter companies, I never get the same recommendations from different companies. If the science was good I should get the same basic setup recommendations from every company, but every company gives me a different take on what the car needs. So in my experience you simply have to buy several and sell the ones that don't work out. For example I have asked for advice on camshafts from several companies and the grinds are usually very similar, so I trust those recommendations and just go with the best service. But to answer the post, if you want to see big changes better cylinder heads and more cubic inches, most other things are usually just small increases in performance. And in my experience many times the small things you change may not show quicker ET slips, but I see improvements in consistency, which tells me there was an issue that needed to be fixed.

just throw it together like i do,only people that make over 6 digits can aford dynos and be so anal about everything,im a average working man,i cant spend all that big money

I second second this!

I sealed my 6PK scoop to my carb... worth a tenth and 1.5mph. Removed it and jetted down, lost everywhere...jetted back up and gained some, sealed and gained all back. Jetted up from there with it sealed and lost.
Working on the car, specifically the front and rear suspension, and launch were the biggest gains.

Found the same exact thing with my air pans. Guaranteed 1-1.5 on both cars I tested them on that have 6 pack scoops. The hemi scoops would probably pick up 2 tenths lol.

Never picked up so much for so cheap.

You may have had good results without, and I suspect you have based on your response but wouldn't say dyno time is only for rich people.

Isn't that expensive to baseline your combo and do testing from that point on.

Isn't the track the best dyno?
It took me awhile to figure out I could not make drag race motors get the best tune on a engine dyno sitting still inside a dyno room

Cam tming. We experimented with a symetrical pattern comp cam around .740 Lift with 1.6 arms. We retarded it 4 degrees and picked a solid 1 1/2 tenths no other changes. Easy enough to do with a Jesel belt drive. FWIW the Indy CM3 (Asymetrical) in there now is best straight up. Don't ask me how I know

I agree overall light is right, but placing weight in the correct areas will be a benefit.
I got a few of those weight tubes added lead shot and scaled the car. Got the car to 49% front
51% rear. More consistent 60 foots and a tenth better et.

I agree with the converter comment very much. Also the 727-904 swap is worth ET every time.

If the converter is correct it almost washes out rear gear choice. I went from 3.91 to 4.56 when I broke my 3.91s. The time slip didn't change hardly at all, it was spinning lots more RPM in the traps but that's it. I have seen other people with a good converter do the same type changes and net nothing ET wise. But a car without "enough" or "the right" converter will usually move a fair amount of ET with gear changes.

What worked best for me back in 1991, my '69 Cuda 3300lbs with home built 446ci motor, 6pk bottom end, Team G, 850DP, 9.8:1, 4800 stall, stock 906's, ran a best of 11.2@118+. Did nothing else but bolt on some 2.14/1.81 906's mildly ported to around 260cfm with HS r/rockers and went 10.7@125 first pass NA. Was running the old MCandless .650"/290@.050 sft cam, and they say it needed 12.5:1 to work, how much faster would it have gone@12.5:1, not that much more I doubt, perhaps a 1/10th?...and there was quite a lot wrong with the car, too loose front end, would top out and not enough air in the 32's to name but 2, would've been a 10.5 car with those sorted.

I learned things on the dyno that wouldn't have been nearly as obvious if all I was going by was an ET slip, a really good example being valve train instability issues.

I learned things on the track that the dyno wouldn't reveal, in one example being two carbs that dynoed virtually identical, but the one that had better shift recovery on the track being worth .1+ MPH and .1+ quicker.

The OP mentioned straightening the lifter bores... Assuming he means bushing them along with blueprinting their locations, I understand the oil control benefits. But is there a measurable performance improvement?"

EDIT: This is of interest to me because my current block has had the lifter bores corrected bushed, but it's "tired" and the cylinders couldn't take anything more than a re-hone during the last rebuild. I've got a freshly machined block to replace it, but the one job the shop that did the work wasn't equipped to do was the lifter bores. Not sure if I should plan to haul it somewhere else to get that done, or build it as is.

Another thing I tried was 2 Pro Systems 750's in place of the Eddy 750's Plug check looked good. Gained 1 mph and .05 in ET. Not worth the cost to make the switch.
Doug

Well, straight push rod angles, 55mm cams, vacuum pumps, dry sump systems, rocker arm geometry, heavy vs lightweight crankshafts, steel vs aluminum rods, ring packs, ect. all effect longevity IMO. If you want to make more power, add CI, heads, camshaft, compression, and fuel system that works with the CI you choose. Then match the converter to that combo.
Weight of the car is always a factor as the old saying goes, "less is more". That said, lightweight crankshafts only RPM faster. They don't really make more power unless you're a comp eliminator guy and use 7" converters and even then the improvement is minimal. A center counter weighted crankshaft weight a lot more than a non center counter weight weighted crankshaft, but it is much less prone to cause main cap chatter.
Look at the stock/super stock/comp eliminator guys. They get the most out of their parts, and they are pros at picking the right converter for their combo. That is the key as mentioned early in this thread. JMO
By the way OP, this is the best post I've seen hear in a long time!

Yes and yes.

hoping i cam get my charger out this year, first time since 2007.
hoping i can crack the mid 11's with .030 over 440, 11.5:1 RPM heads, 3.91/29" tire. [or close ]

1/8 mile ? ....

Words of wisdom from a Super Stock racer... Make your best LOW friction short block assembly, choose your best roller cam for your cylinder head flow rate, then hang an induction system that is not a torque limiting device (headers included). After all is done with the engine choose a converter that will flash between 6400 and 6800 rpm (done the data acquisition). REMEMBER this is Super Stock racing! The rest is low rotating mass components for the drivetrain. AND one final thing is the best shock program (shocks) money can buy for your budget that is monitored with data acquisition.

DATA IS YOUR FRIEND

3500# car, 400c.i. engine, 1.21 60' , 9.20's

Plug wires-I’ve has MSD, Ultra40’s and Firecore over the years. Each supposedly better than the last and never have I seen one bit of difference. I’ve always disliked the MSD’s and how they don’t “click” on as good. But never changed any et.

Good clutch-screw the torque converter.

10deg locks vs 7deg locks. Last time I had the heads freshened he was all about I think going from 10 to 7. Spent a bunch on ti retainers and locks. The time before that I could have swore he wanted it the other way. I don’t remember. But I have never seen a change in lash, et or anything else from one to the other. Heck if I know.

My M/T 3074s were worth .03 in 60’ over Phoenix. A little lighter and seem to last a little better.

I bought a used 1250 Doninator years ago from a local guy. Threw a kit in it and away I went. Sent it to Pro-Systems couple years later. $600 bucks or whatever it was. No difference. Maybe idled a little cleaner. I still wonder how much it all matters in a stick car that’s never below 5k but I’m not smart either.

Well in my opinion its all about a combination so there are many roads to success.

In my experience good results have come from high compression, lightweight engine components, vacuum pumps and certainly not least quality torque converters and transmissions.

I also feel that strong pushrods, quality rocker arms and with a roller cam stout spring pressures are important.

While it can be expensive I think Andy F has shown that money spent with folks like Wilson can be rewarded.

Of course all of this would be tempered by what do you want to do? Just go fast, run brackets, indexes, small tire, NHRA classes etc.

Good luck with it!

For me it was going from B1 original's to the PSO head along with a 55MM .900 lift cam...While I gained around 100hp thru out the RPM range it ran right by my 20yr old chassis capabilities...We have to take so much power out to be able to get down the track that we're still stuck in the high 4.70 to low .80's and need to be in the mid 60's...So now it looks like chassis prison and another lost season !!

I have not seen anyone or I missed it, talk about Carbon Fiber Drive shafts and or Polished finish on the rear gears, what if any did they pick up.

There was a post on Classracer about lightweight ring gears and the finishes came up.

http://classracer.com/classforum/showthread.php?t=75119

Well, it's supposed to be worth 20 hp if you believe THIS DYNO TEST

My Indy Maxx block has never had as much pan vac as it has after BES honed it. And he told me to run it as cold as possible 100* if I can at the starting line

let me borrow the engine....LOL
why cant your ladder bars handle the power??

Barton has claimed HP increases from it, too. My first thought after reading the article was... how far off was the lifter bore alignment to have made that much difference? Regardless, thanks for the link.

Barton has claimed HP increases from it, too. My first thought after reading the article was... how far off was the lifter bore alignment to have made that much difference? Regardless, thanks for the link. [/quote]

The lack of a deck plate use surprises me. I thought that was standard in any HP build. The difference is plate honing cost is minimal in my area, so why not make every effort to maintain block integrity?

Boost. Never fails.

YEP! Seen many combos that don't run as good as they should due to the converter. And vice-versa.

I Feel my junk runs pretty good without it. I guess the R3 block in my Duster now has been bored with deck plates but not by me, and when I rebuild it over the winter I will be hand honing it myself. My machine shop that I use probably doesn’t even have a small block Mopar deck plate. I never bothered to ask.

Working ON THE CAR can be huge!

Once upon a time...

Roller cammed 440 in a back half E body. 10.80's @ 124. Fresh trans and tuned up converter, new HAL (now QA1) adjustable shocks on all four corners, opening valve lash .010: 10.40's @ 127 were the result. Added a rear tire that was 1.5" bigger in roll out: 10.30's @ 128, best of 10.36 @ 129.

10.80's to 10.30's and other than the valve lash, never touched the motor, or the tune up.

When I took my 4.380" RB block in to get a touch-up hone before the last reassembly, the machinist who does my block work now told me he tried to do it w/ a torque plate first, but it distorted the cylinders too much. That surprised me because when the block was bored to 4.380" by another shop (who, even if still in business, I won't deal with) I specifically paid to have the block deck-honed... and the receipt states clearly that I paid the additional charge for it.

I told this to the machinist and his response was: "Well, he may have put a torque plate on it... but he sure as He11 didn't tighten it down." This guy prepped my other block, which is a 4.375" finished-honed w/ a torque plate. And I've been wondering even before this thread started whether the 4.375" block done "right" will actually make any more power than the "tired" 4.380" block w/ out-of-round bores and excessive piston-to-wall clearances. I'm not sure I'd bet on even a 10 HP improvement, but a scientific A-B comparison test ain't gonna happen, much as I'd like to know.

Just a few things I can think of right now that I've seen from running my own stuff...

1. A vacuum pump only helps w/ oil leaks on a mid 9 sec NA 572. Saw zero performance difference, but it did stop the little annoying oil leaks. Had low tension rings in it too. Might work better on other combos, but I certainly don't think it's worth it.

2. I ran my 572 hemi for 13 years and freshened it up a couple times in that time frame. Obviously it got more and more worn at every freshen up...speaking about the pistons and bores. A simple dingle berry hone and re-ring and it ran just as fast as it did when it was fresh. Even though the wall clearance had grown .003" and had .002" taper and out of round.

3. Zero difference b/t spark plug wires. MSD, Taylor, and Firecore...pick the ones that LOOK good to you, b/c they will run the same. I think the ignition market has more gimmick sales pitches than any other...well, maybe motor oil has more.

4. A couple of my engines that ran very well for what they were, weren't honed w/ torque plates. My hemi was done w/ one and I recently bought my own plate b/c no one around here had one. Not saying they aren't a good idea, but I have no idea what it's worth power-wise and a lot of folks seem to think it's worth 200 hp, lol. I know on my hemi, the bore is out of round .001" without the plate bolted down. See my 2nd example above for thoughts on that.

It's really cool to see this kind of transparency re: hand honing and even ball honing, as it matches up to a few discussions
I've had with folks I consider smarter than me.

Chip,
Everyone's experience can be different on this.

On my 700 hp 346 inch small block the higher you crank the vacuum the more horsepower you get. My memory fails me on the specifics but I think at 10" its worth about 10 HP and if I went to Pro Stock territory over 15.

My biggest issue has been getting the engine really sealed up to hold vacuum. I ended up getting a cheap smoke system to test for leaks to prevent the dreaded dyno embarrassment.

That all being said I have seen many knowledgeable folks like yourself with experiences exactly like yours. However I think its something anyone serious should at least try, especially if they have a light ring pack.

Bill

for us: 3450 lbs car and driver, 512 .indy heads etc:
Removing mechanical fan and going electric, dropped a .02 et
Wilson ported intake , dropped just shy of a tenth.
new converter, cope racing trans- dropped et and improved 60ft.
Dual adjustable front shocks and single adjustable rears - improved 60 ft and et.
Data gathering of afr/vacuum/rpm allowed us to tune and really made us consistent and faster.
Went from 6.72 to a best of 6.38 and car is really consistent in running what Da allows.
( 1/8 mile numbers)

Other than that, just a basic/solid built 511 , low maintenance set up .

Curious here...What is your 60'...

went from low to mid 1.50's to 1.38-140"s , will be looking for sub 1.35's this year.
Best last year was a 1.36.
Folks around here say we cant get it to low 130"s so, its a quest to prove them wrong .
Biggest problem on our 60ft's seems to be the cam we have , its just a little .625 /625 at 275@ 50

I think there is lots of re boxing there. That wire has uses for industrial stuff and I am sure the Ignition guys just pick out a wire they like and then build stuff from there. Whoever actually makes the wire is probably way larger than MSD or Taylor or FireCore.

I bought some summit branded cut to fit stuff for my coil near plug setup. $43 nice quality wire that has to be made by Taylor or whoever makes Taylor's stuff. The boot style, wire color, and feel sure feel like Taylor or whomever makes wire for Taylor.

Note: I am no expert so nobody get upset because its just my observation lol

Thanks!

I went from Taylors to Firecore. Zero difference in performance but the Firecore fit is PERFECT out of the box! Very happy with those wires for that reason alone.

There is no doubt they pump out some nice stuff. But the ready made kits for small block Mopars with GM LS Truck coils is pretty slim haha.

Your welcome.
Its a 65 plymouth belvedere if that helps.
Guys on the board have really helped us with chassis and other areas.
we also added a 1200 twinblade and Dom ( Thumpercarbs ) has certainly been a factor in improving the car.
If i can get this Duster done, see what it does and its basically the same ideas from the op- simple, strong, low maintenance stuff that just works.

Imho: best single item anyone can buy is a af meter with built in data logger so you can see your afr for the whole run on a computer screen.
We build cars here and install them as standard equipment - customer has an engine problem i can pull the last logs and see rpm, afr, vacuum and those three certainly help with diagnosis .
Race cars: even with classes that don't allow taking data, one can get on top of things during "test n tune " and its just charting weather after that because you know where you are.

To date- every car i have tuned with one i have made faster, its one of those 'best hp per dollar " deals to me.
Aem makes a nice little single unit that works very well.
imho

Interesting replies here, in terms of what some see and not "worth it" versus what others results have been. I think a caveat to the question should be what is the intended purpose of the engine and race program. I certainly will approach a 10 second bracket build differently that a heads up car. I think this is a VERY valid argument to be made. Yes we still approach the 10 second bracket build with the same professionalism but there are things you simply DO NOT need to do to build something that will live in that world that you absolutely MUST DO in a heads up deal. Intended purpose and goals is what matter. Having said that round is round, flat is flat and that will never change. Quality machine work is always important no matter the level. And often times is the difference between that 500" Indy motor that runs mid 10's vs the one that runs mid 9's with basically the same components. There is power in things as simple as a valve job. Properly matched components in another issue that I see a lot of. Lastly I don't think most people who are looking to get everything out of a combo are willing to pout in the time and testing it takes to separate themselves from the rest.

As for what I've seen work in terms of performance or longevity, most have been mentioned. Center counter weight cranks, proper lifter location and angle, bigger cam cores, hipped blocks/heads, smaller ring pack, lighter/stronger pistons, valvetrain CONTROL, cylinder head development(this NEVER ends), intake evolution(also NEVER ends), more compression ESPECIALLY in aluminum blocks(numbers that most we be scared of), oil control, oil pressure, oil viscosities, carburetion(see heads and intake) are just a few of the things I have seen that make a difference. Not even to get into torque converters, low friction transmission and ratios, low friction third members and =gear treatments and fluids, low friction bearings in the drivetrain, chassis tuning etc etc

The same things do not apply equally to every engine, or even engine type.
Useful stuff also varies widely as to benefit per dollar spent.

Back in the days when dyno's or data acq weren't as available. Footbraking I've seen alot out of carburetors. specifically tuning them to the application. One item i feel gets overlooked is directing cold air into the carb cleanly. Not many believe me but we saw on a car i tuned about 3mph and.15 immediate reduction in ET going from a 6pac scoop to a bigger 'pro' scoop that was placed better irt the carb and clean air. That made us realize, there was more in the 60ft thereafter and gained more. Went from mid-high 10's into the lower 10's solidly. SOME of you get lucky occasionally and things fall in-line but, if they don't most people arent willing to find what SHOULD be there in 'performance'. That said, some bracket guys i know of that make big number of passes usually have there stuff sorted-out pretty good more likely because they are 'doing' things rather than talking about the theory.

Happy valvetrain, good sealing short block and heads, convertor and chassis package. I think the most important thing is working with what you have. Make one change at a time. Too many racers change 3 things at once and never really know what change made the pick up or loss. Data systems take the guesswork out of it. And I personally think engine dyno sessions are well worth the money. Gives you a baseline for everything.

Glyptal or other coatings in engines for oil drainback. Anybody ever test to see if there is a significant difference?

And lets be honest sometimes taking weight out of the car means taking weight off of us.

I use to do that a lot. One build had the Glyptol come off in sheets. I'm very particular about the metal prep before painting the inside. There is such a thing as oil impregnating the iron. Found this on other industrial iron that I had painted in the past. I now remove all the foundry flashing and prep whatever I can to make the cast iron as smooth as possible. Prep time vs the price of Glyptol is worth it.

I had the exact opposite affect as others in regards to hood scoops and sealing it to the carb. I lost my WO scoop at Quaker City one night, next round broke out by (if I recall) .08 off the gas, running an ET that was unusual for the car. What I figured was the scoop was catching more air than the car could consume and was acting as a sail.

I don’t have much to add here but am trying to learn. I’m most confused by camshaft lsa and what works best. For a street car with 3500 stall vs race car with 5000?! What has worked best? Also curious about overcamming a motor with small heads for the cubes. What works?

The things that continually surprises me on camshafts are:

1) How much more important duration is than lift on the cam. Getting the duration right, for the CID and headflow, is way more important then squeezing every .001" of lift out of the cam.

2) How much more important duration is than the lobe profile itself. Even when we talk about "Best lobe profiles"... If the motor combo wants a 260@.050" duration cam, worrying about which lobe profile you're going to use at 250@.050" won't do you any good at all!

Biggest changes i have consistently seen always involve heads and cam matched nicely, along with torque convertor.
Such changes can often result in huge gains.
Last time i saw such big changes was with current car.
Stock shortblock 360 with factory a mile in the hole slugs, 750 carb, 4.10 gear, comp cams generic flat tappet 280 ish advertized cam, stock eddie heads( looked over and checked before use.
This combo what was in my current car when i bought it.
Took it to the track on a good air day, 12.20’s at 108-109

Took heads off, whacked 40 thou off, had them mildly ported in quickie single evening type job, installed a known good 950 carb i had, installed Howards flat tappet closer to what i thought would make more power, and returned to the track with just those mods......
Milled and lightly ported heads, cam swap, carb swap
11.20’s at almost 119 after little tuning....in good air
Good heads, matching cam, good carb, bit more compression...
Full second and 10 mph
Same gears, vert, headers, weight, etc, etc

Interesting topic, wish I knew the answers.
I just have a street car, so once I got to the mid 11's more power slowed my '60 times but added to top end MPH. Besides the car has no rollbar.
I do think the entire vehicle needs to be considered when making engine changes.
For example, is 10 more peak HP worth a loss of 20 ft/lbs in the mid range. If the converter and gear operate near peak HP, then it should be quicker. If your geared more for street with a tighter converter, than maybe not?
Since when I race it is just bracket racing, consistency is more important than running a specific number.
I try to find parts that don't create alot of problems. I have had several different sets of spark plug wires, all which ran about the same when new, but after time I have had them melt. crack, burn, have the terminal ends pull off, or not snap on well.
Currently using the Accel 9000 with ceramic ends. Haven't had them on that long, so I will see how they hold up.
Engine wise, I think many overlook using the correct length and type (diameter, material, thickness and hardening) of pushrods.
Controlling fluids like oil and fuel would be another. If your car pulls just 1G acceleartion, the fluids are going to flow to the rear of the oil pan, gas tank, and carb bowls as if the car was setting at a 45-degree angle.

One surprsing gain I had was tires. I ran a few weeks on a 28x10.5 stiff wall tire a friend gave me. I moved from that tire to a pro bracket radial in the same size and shaved a good .05-.08 off the 60ft time.

I run a high resolution driveshaft sensor and there was no traction problems with the bias tire. They did have a different curve on the driveshaft speed but I believe the difference was the sidewall wrapping up on the bias tire because it was at the hit and for a microsecond.

It ran better MPH on the bias tire but that is because the engine was tapped out on RPM due to a forced gear change(broken 8.75).

I am terrible at note taking and logging passes. My Dad takes all my slips at the end of the day and logs them into a spreadsheet with the splits on it(Thanks Dad!). But I don't add enough notes to look back a year or two and remember what I changed

Where to start -

First, there are no "tricks", pay attention to the basics - quality machine work, quality induction work, quality piston/ring/cylinder sealing, reduce friction where you can, reduce oil flow/oil pump PSI when you can, use as large of an oil pan that will fit and only enough oil to maintain PSI through the run. correctly sized header primaries/merge collector.

The .9mm,.9mm, 3mm ring combo was 10 hp avg. better than the .043, .043, 3mm ring combo in a SBC in very controlled ABA conditions, not sure why your results didn't mirror those?

And that was with leaving the top ring in the same position - Another advantage with the smaller ring package is that the ring radial widths are .125" vs. .155", allowing the top ring position to be moved up on the piston, proven power there too.

We have built set on kill engines of all sizes and have found air flow is king, we make the same hp with a 565 as we did with a 632. The thing with the 565 was it was much easier to race. e were definitely faster with the 565. these engines were raced in nmca 10.5 . we were normally in the top 1/3rd of the field qualifying . I would like to see where we out ran the head flow. It would be my guess around 520 inches. So with all that air flow is the name of the game in my opinion.