Guys!

I'm making a few tiny adjustments to my factory 596 heads (previously DIY ported using the MP templates).

This is what the heads looked-like when I had finished them up:



My current adjustments really just thin out the valve guide boss further (slim it down). I also would like to remove the roof bump as in the following photo (keep in mind, the head is upside-down, so deck is pointing up):



My original attemp to do this resulted in breaking through, luckily this was on the sunk-in head-bolt, so epoxy took care of the issue, here is what that looked like:



...and the fix looks like this:



Alright...so as best as I can there I should not have this type of an issue with any other ports...the head-bolts there all are raised. Also, as best as i can tell there is no WATER passage in this area...is that correct?

Or is this a bad idea?

You should have made a spacer and let it fill the hole. Then you can grind the port out to where you want it. Then you use the longer head bolt.

Pretty nice work.

Pay berry close attention to the valve job, especially the top cut.wider is better.

And you can grind out into the valve cover bolt hole and get rid of the lump. I've never had one leak.

The old Chrysler Power magazine, November 1991 issue had a pretty good article on porting small block heads.
It would have been a better article with more proof reading as it has several typos in it where the side chart has some differences that does not match the data in the article?
I think the most interesting part was the exhaust flow did not respond too much to porting, but did respond well to using an exhaust valve with a tulip style head?
They also found filling the intake floor helped velocity while not hurting flow, so no need to take metal away from the port floor.
As expected most gains were in porting the bowls, and valve job. I think they back cut the intake valves too.

And you can grind out into the valve cover bolt hole and get rid of the lump. I've never had one leak.

I epoxy studs in the vc holes and contour them as well.

If your thin on the tube side this is cheap easy backup, and most holes need very little prep.

I epoxy the heck out of them and if they are tight, leave a 1/2 inch and use a wood block and a bfh, then trim them.

As with many OE heads, when you start trying to get a lot more air through the ports, the short turn starts to become an issue.
SB mopar heads are no different.

My experience has been that trying to completely remove the humps in the roof by the head bolts is worth almost nothing unless it's a truly MAX effort deal.

The short turn needs to be layed back as much as you dare...... And yes, there is water right there, so use caution.
This is the one key area of the intake port that is noticeably different in an X head than the other SB mopar heads. The short turn is already layed back quite a bit compared to any other stock SB mopar head, if they both have a 2.02 valve.
I find it fairly difficult to get these heads to not start to back up(turbulence) at much over .500 lift, if you've got the rest of the port opened up to allow a noticeable increase in airflow(say around 240cfm and up).
What I often do is use 2.055/1.625 SBC valves, which provides a nice flow increase in the area under curve, although it doesn't help with the ports backing up at high lifts.
If you're starting from scratch, the 1.625 exhaust valve is an easy way to perk up the flow.

Did you end up using studs there or just a straight forward valve cover bolt?

Seems like this would be an easy way to remove a sizeable bump in an otherwise tight port area...but I've ready various on-line stories of ensuing constant oil leaks, etc, etc...

Hmm...well, a few years back when I was really putting some serious time into porting these I wish I had this info (re: tubes) as I would have most likely tried to do this on my own. At this point in time I am really just looking for small (read: easy...LOL) improvements as I indend to start by W2 stroker build this winter and am really only looking for another 1-2 yrs use out of these heads...certainly not a max-effort type either.

Good info to have, part number/brand name saved!!!

I've used both a stud and a bolt. Never had a leak. The heads I'm using now have broke through all the upper valve cover bolts and I'm using a bolt with no leaks.

I have W2's with everything to swap them out. Just needs to do them up.

Yeah...certainly this is NOT one of these MAX effort situations...only looking for easy improvements. As-is, here are the port flow numbers off of a SF-600 bench:

LIFT I E

0.100 67 57
0.150 99 79
0.200 130 104
0.250 162 125
0.300 189 140
0.350 215 152
0.400 235 160
0.450 253 167
0.500 262 172
0.550 261 175
0.600 248 177


So I think I saw precisely that behaviour with my heads...the flow numbers started dropping off right at the .550" mark.


If I was re-doing this, yes, I would probably go with a 2.05" valve, but for now, it stays as-is. No more money to sink into these casting...I am saving up for the W2 Econo heads next...LOL.

When you go to a bigger valve, it makes the port break over and go turbulent sooner. You can't get enough port area above the short turn and you can't slow the air over the short turn no matter what you do.

You are at the point of making sure the chamber and the valve job are as good as you can get. Pay very close attention to the top cut. Even if you lose flow, if the chamber/top cut are good you will make more HP.

Make sure you lift average and get as much lift as you can. Even past the point of flow back up.

Those are pretty good numbers for that level of work.
Pretty close to what my old 587's flowed that I ran on my 340.
That motor made 478hp with flow numbers like that.

You can go farther. M/P made a kit with a pair of plugs and 2 of the longer head bolts. Counterbore varys from head to head so I make my own plugs to fit each head perfectly. Get a head bolt kit for W2 heads and it has 4 of the longer bolts. If you are careful, you can get 1.02" through the pushrod pinch without tubes.

I have read stuff about the MP plugs before, but never knew what they were used for...now I do...thanks!

So how do you make your own? What do you use? Is this something you machine, or have someone machine for you?

I machined mine out of aluminum on the lathe. I epoxied them in and the ground them flush in the port.

Ahh...well, I'd love to have that option...but no-go...and machining something locally would just set me back several weeks.

OK, for now I'm going to play it safe and just attempt the valve-cover bolt clearaning in the roof and nothing more. That should be plenty enough...right now this is what my blending of the guide boss looks like:

Your work looks good. Watch the area of the Shortside radius on the long wall. There is water underneath that hump if you try to grind it out. Laying it back will pick up flow but if you go to far you will hit water. I did my first set nearly 30 years ago in my parents basement using a green black and decker 3/8 drill and a bunch of Stones I got from somewhere. I was hooked from that point on. Don't be afraid of making mistakes in the process of learning but only risk what you can afford. If it is your only set of heads be careful and don't push the envelope. If you can get a Junkhead to play with. I had it bad! I would buy expensive head is just to play with and know that they were going to be jumped when I was gone. But I learned a lot through it all. When the Buicks came out I played with them. When the Brod when big dork Buicks came out I played with them. When Brodix came out with the CV/SP 330 I bought a set of them too. W2's, a set of Battens years ago....I bought a set of w9's to rip around on....actually 1000's of hours grinding, flowing, testing, probing....had an SF-110 for years them sold it and took a few years off....read that 'bad relationship'!... That passed and I bought an SF-600 and continued!!
It truly CAN BE an addiction!!!
Keep up the good work....be patient and most important have fun!

About the valve cover bolt boss...don't worry about it! Grind it out! Years ago...in the early 90's I worked for a guy that did a lot of rounds rounders. They used 9:1 358, no porting...1" in from valve seat and 1" in from intake face. They had to use stock block, a factory head...the Chevys could use a bow tie...any cast manifold and a 650 Holley on alky. When I started they were dynoing right around 435 hp. I started doing the heads and when I left we were making 585-595hp!!! We were ALWAYS tech'd...they all thought we were cheating but the heads always passed! We had track champions at almost all the tracks and always had guys up front! Our stuff was fast!!!! Everybody wanted a CMS Racing Engines motor back then!
Back then it was taboo to touch the SSR and the closed chambers were thought to be the best because they could make compression. When the second gen bow tie heads came out they had a bathtub type chamber versus the first gens which were more of a semi-open design. I remember the first time I started laying back the SS and the chamber and everyone told me that you can't do that. I even saw a lot of Slawko stuff from the time and they never did either. I was told "look at them...they are the pros"..."you ruined those heads"...until the flow numbers went from the high 120's @ 10"....an SF-110 back then....to 155-158@ 10" and we made TONS of power....these days every one knows those areas can give the biggest gains but also the biggest heartaches....ask me how I know....
My point is that almost everyone of those heads had the boss ground out and I never thought twice about it!

My reminiscing yesterday brought up a memory of the 'trickest' heads we had ever seen at that time. The guy I worked for was friends with Dan Jesel and one of his salesmen at the time, Jerry, would stop by from time to time. Back then these guys would grudge race their cars for big money and Jerry had at least an interest in one of the cars. From what I heard at the time there were few rules....had to be streetable and driven to the track. Again from what I heard a few would trailer the car to get close then drive the last little bit. I remember the engine was a 434 with a dry sump and sheet metal intake. The heads were Brodix -12's that had the intake port raised 3/4". The heads were completely welded on the topic the ports, valve cover rail and floor to raise them up. I remember because my boss gave me the heads and told me to take them home to see if there was anything we could do with them to make them flow better. I distinctly remember they flowed 339. That was converted to 28" from whatever they flowed at 10. That was a lot of air for the time and I recall the engine making in the mid 800's. I remember doing some probing and mapping and thinking we could get more out of them but we never did because Jerry didn't want to risk messing up a set of heads he had so much money tied up in. This was right before the CV/SP's came out and when they did they made the switch. By now I no longer worked there but kept in touch . I remember them being the first head I ever heard of flowing near 370-380. Eventually they got the flow up to around 405 and the engine made right around 1000hp. That was a ton for back then in a 'street' car. From what I was told too the car was a late model Camaro and looked like a total rag....which was always appealing to me...,paint don't make it fast

Thanks for the feedback and the great story-telling...I always love reading this type of stuff because to me anyways it tells a tale of someone learing, trying things and figuring them out. That is utlimately what makes it fun for me. Your porting adventures are pretty similiar to my experience...the first set of heads was quite a learning lesson...I managed to use them...but it was the 2nd set where "all of a sudden" I felt like a pro...only to massively break through the port into the water...ha ha...oops...

Truth be told, I really didn't have a reason to pull the heads off the motor...but since I wanted to freshen them up and the static CR bump along with some further porting/streamlining were just "around the corner" I figured I'd give it a try.

So far I'm done with one of the heads...about 2/3 done with the 2nd one. Need to get to the intake side of the port now and gasket match along with slight widening and roof bump removal.

For what it's worth...I made myself a Helgesen E-bar tool...LOL...what an "adventure"...clubbered the thing out of some threaded rods (I'll post a pic later, meanwhile I've attached a pic of the genuine item) and to the best of my understanding the measuring capability comes from the distance of the meassuring bar and both the bottom and top bars (must be the same). On my heads I unfortunately have an off-set drilled pushrod holes, so while the one side can be opened up to the full 1" width, the twin port could only go about 0.9"...my tool would show a reasonable about of thickness left but on the thin side (0.9" width) I would actually close up the gap...so I think my tool is ever-so-slightly off since I'm not getting a true reading on that side.

Well you guys...the results are in, brought one of the heads to the same shop that did the flow test originally (same machine, etc)...actually had the same guy do the work (since I brought the original flow sheet write-up with me and he could tell it was his).

For completeness sake, here are the BEFORE & AFTER numbers for the INTAKE port only flow (no changes to exhaust):

LIFT - BEFORE - AFTER - %CHANGE

0.100 - 67 - 67 - 0
0.150 - 99 - 102 - 3
0.200 - 130 - 138 - 6
0.250 - 162 - 175 - 8
0.300 - 189 - 205 - 8
0.350 - 215 - 232 - 8
0.400 - 235 - 253 - 7
0.450 - 253 - 267 - 6
0.500 - 262 - 282 - 8
0.550 - 261 - 291 - 12
0.600 - 248 - 283 - 14

Sooo...while I love the bigger numbers, I need your feedback re: is this a reasonable improvement given the work I did? Or are the numbers too "optimistic"???

The flow bench guy said: "...I checked the numbers over, they seemed high for the size of the ports (bowl, lack of any significant short-side-radius work, etc) but they were consistent...seems like a good flow...".

To me they make sense...the low lift stuff matches pretty well and at higher lifts things really take off, I assume this is due to easier less obstructed port roof.

Here are a couple of shots I managed to take to capture the final shape:

Wow. Those are W2 flow numbers from a P-car head. Pretty good.
How many hours you got in them?

Those are good numbers but not W2 numbers. Also, a W2 flowing 290 CFM will make way more HP than a Pcar head flowing the same. Don't get caught up in the numbers.

That said, you need to figure out how to NET .650-.660 lift and that will be almost impossible with standard length valves. If you install longer valves, you will be hard pressed to get the geometry back in shape.

Never say never i guess, but that's a big number for a 2.02 valve at only .550 lift from an OE head.

I would have tested another port if I saw numbers like that, as verification.

Yep, look at the numbers at .300 and .400 too...

I would be very HAPPY to check a set of my Edelbrock heads on that flowbench.

I ignore the .550 and .600 lift numbers. I'm within a few CFM on a 2.02 valve on a Flow Data bench. But I know, for a fact, he and I use a different valve job.

The rest of his numbers are close.

Well, this last set of changes at most 1.5-2hrs a port...maybe not even. All I really did was to remove the left-over valve guide boss casting that sloped away and into the roof...I tried to make that as "steep" as possible by basically removeing as much of the material as possible but without joepardizing the guide support that's needed. It is by no means nowhere near some of the pics I've seen floating around where literaly just the guide itself is left in place. I'm just not that brave...LOL...

In making these changes I suppose my goal was to increase the .500-.600 flow, here is why: my current cam is Hughes HE3844 hydraulic flat tappet. Lift @ 1.5 ratio is .536/.540, but with 1.6 ratio it is .571/.576.

I do in fact have a set of Crane iron 1.6 ratio rockers and have been intending to actually do an "at the track" change between the two to understand what impact that has on my combination. Really just a poor man's attempt at maximizing the combo while learning a thing or two while I'm at it.

If that head flowed 291 @ .550 on my bench, it would be the same as the Competition CNC ported TFS 230cc SBC head with a 2.08 valve, flowed on a 4.00" bore, that I tested a couple of weeks ago.

Do I think that head would flow that on my bench? No.
But I also won't say it's out of the question.

I'm a firm believer that you can't really compare numbers from different benches.

Another thing is......
When they're your own heads, you can spend as much time on them as you like.
When you're having someone pay you to do it, if you take too long, you end up putting in extra time that you can't really charge for.
Porting a set of OE iron heads only commands so many dollars.
I can do a set of X heads in 20-22hrs. That isn't a "max effort" type of job, but I basic "full port and polish", including the chambers.
With a 2.055 11/32 stem valve they'll flow 275-280 @ .550 lift, without putting any holes in them other than perhaps the valve cover bolt hole.

It looks like you may have done more work around the guide at the roof, but then the X head has a better short turn....... Could be a wash.

That is a bit high at .550 lift but the rest of the curve is very good for that valve size. Mine flow within a few of what he has, on an entirely different bench. My issue is that he is a bit high over .550 but they should run well.

I purposely used a 2.02 valve.