[GTOGEORGE]

Pontiac is what it is. That doesn't mean we can't improve on it.

GTO George

[Tom Vaught]

Post up your ideas on how we are going to improve things.

Tom Vaught

[65nss4spdGTO]

Back in the 90's, long time alcohol funny car driver and engine builder Fred Mandoline's shop was next to my dads. We learned a great deal from Fred as he felt our Pontiac's were so head restrictive, he wondered why we wasted our time with them. Later on, Fred built inertia dynos for Brad Anderson.

From what I remember, most of those engines were in the 450 ci range. The heads are are big, meaty pieces and the decks are tall.

Calvin Hill
Hill Performance
708-250-7420

[65nss4spdGTO]

These are my builder thoughts on a good blower build for a Pontiac. If something seems out of line, please provide your thoughts.

3.750" to 4'000" stroke, rod length in the 6.635" to 6.700" range, I want a piston with a long skirt to help stability, rings down off the top .350"-.400". Stout piston pins with a bridge style pistons, maximum valve train stability, extreme alloy valves. and a superior cooling system, dry decked and O-ringed.

Calvin Hill
Hill Performance
708-250-7420

[Travis Q]

Very good so far.

Don't forget the Hemi size pins if its a high power build.

[Elarson]

Originally Posted by GTOGEORGE

Doesn't matter what head you have 10 studs won't seal it.

GTO George

Good news....so far the Boss Bird heads are sealing great. We use the same (10) stud pattern, upgraded to 9/16" studs. And the billet heads are way, way stiffer than other heads (intentionally designed from the ground up with lots of meat around the bolt holes). So, 2 ways to skin a cat.....lots of bolts with a flexible head or fewer bolts with a stiff head.

Eric

[GTOGEORGE]

Cool!


GTO George

[Travis Q]

Eric, I agree with you. I have tuned on some Big Fords that only have ten head bolts as well, and they are 9/16"....they didn't have sealing issues, and were making some big power. This, in reality, is probably the best solution going forward for a "best case" boosted cylinder head. It gets around all the issues associated with putting in extra bolt holes. I think one of the most overlooked keys to making it work is something you have hammered on a couple of times: keeping a lot of material around the bolt hole for good column strength. i think this is where a lot of the cast heads fall way short, in the name of better flow.

[Tom Vaught]

1.030" Hemi Pins are the set-up, at least for our power level stuff.

My little 'baby' flow boosted E-Heads (worked on when Jim Valeco ported Marty's Heads and several others at one time) gave up some flow because I told Jim V I did not want him grinding on the head bolt boss between the two intake ports. I was looking for strength there, however little extra strength I could achieve.

Tom Vaught

[GTOGEORGE]

Travis,
Where were the exhaust vales on the Ford heads I'm thinking they were like the KRE Warp 6 heads or RA5. So if 9/16" studs are a help to cure the sealing problem why aren't they standard on the Aftermarket blocks and heads? If you need an aftermarket block and high flow heads then you will probably need the larger head studs. Damn how easy was that!




GTO George

[BruceWilkie]

Originally Posted by Travis Q

Eric, I agree with you. I have tuned on some Big Fords that only have ten head bolts as well, and they are 9/16"....they didn't have sealing issues, and were making some big power. This, in reality, is probably the best solution going forward for a "best case" boosted cylinder head. It gets around all the issues associated with putting in extra bolt holes. I think one of the most overlooked keys to making it work is something you have hammered on a couple of times: keeping a lot of material around the bolt hole for good column strength. i think this is where a lot of the cast heads fall way short, in the name of better flow.

Agree... spread the clamp load!

Larger OD thicker washers also spread load. Perhaps a steel arch for more center pressure between bolt spans.

I have a hunch that if you could make the center of the bolt span on the decks just a smidge higher than at the bolt holes you would move more clamp force to the center of the span.
Technically bending the head.(Ever notice bolting a flat piece to another flat piece the center seems looser than at the fastener?)

Adding smaller fasteners between major spans would help some but getting things placed just right would be key to it helping without creating a new problem.

Tom V, I think lifter bore placement is the obstacle to putting a Brad style head on a Pontiac. Might create valvetrain obstacles.

Eric...good to know on both bolt size and billet thickness.... I think better alloy like 355 would also help vs 356 alloys used by alot of head companies.

[Travis Q]

Originally Posted by GTOGEORGE

Travis,
Where were the exhaust vales on the Ford heads I'm thinking they were like the KRE Warp 6 heads or RA5. So if 9/16" studs are a help to cure the sealing problem why aren't they standard on the Aftermarket blocks and heads? If you need an aftermarket block and high flow heads then you will probably need the larger head studs. Damn how easy was that!




GTO George

I disagree. The problem is that 99.9% of the guys who have the aftermarket blocks and heads DONT need the extra sealing. And the other issue is that the aftermarket heads are all designed to bolt onto a stock block, which uses the 1/2" stud. They are also patterned around the stock layout, which compromises the clamp load of the center three of the top row of studs.

The Ford is a lot like the Warp 6.

And we're not talking about existing heads in this thread, we're talking about what are the design traits that will lend itself well to a boosted head for the Pontiac engine. 9/16" studs will help if the head is designed with them in mind, so it's asinine not to include them as a possibility.

[BruceWilkie]

Originally Posted by GTOGEORGE

Travis,
Where were the exhaust vales on the Ford heads I'm thinking they were like the KRE Warp 6 heads or RA5. So if 9/16" studs are a help to cure the sealing problem why aren't they standard on the Aftermarket blocks and heads? If you need an aftermarket block and high flow heads then you will probably need the larger head studs. Damn how easy was that!




GTO George

A cut back exhaust also takes heat load off the center and end port bolts because it puts the exhaust above the now shortened bolts...heat rises... not perfect on traditional layout but its an improvement. (plus higher ex port has advantages for power) Not sure if shorter bolts expand less when heated but I think so.

SBMopar W series race heads have the port higher than std sbm wedge. They need even more help than our Pontiacs due to head bolts not going to blind bosses.(older production blocks anyway)

[Elarson]

A 9/16" stud on a wimpy head would be a negative, since you would just get more deflection & crushing of the head with a higher clamp load. Note that you would have to bore a bigger hole thru the head, further compromising it's column strength. The stiffer head with lots of meat around the bolt holes has to come first.

Different alloys of aluminum have different strengths, but their stiffnesses are pretty much the same.

Eric

[taff2]

What about siamesed or bifurcated inlet ports? I've done this to my factory iron heads in an attempt to gain port volume but it also opens up a considerable straight line of sight path to the inlet valves,the airflow doesn't have to flow around the pushrod bulge, make a turn to one side and then make another turn to straighten up for the valve opening. The airflow exits the manifold runner exits which are about 2 1/2" square,into a head port which is initially about 2 1/2" square that then gradually necks down as it gets to the valve. Of course you have to use an 'open' intake manifold(like a blower manifold where the port runners don't have a dividing wall) to see the full benefit . I assumed the 'open' manifold and siamesed ports would degrade idle quality and low speed running but this doesn't seem to be the case even with turbos and dual carbs. Fuel distribution looks good so far,but I'm using dual 4bbl carbs on a low rise tunnel ram manifold so I didn't expect any different.
To help keep the heads sealed at my expected 25 psi boost levels I have dry decked them and made up some 1/4" thick ,large diameter (about 1 1/8") hardened steel washers to go under the stud nuts in an effort to 'spread' the clamping loads. If I was running ali heads I would certainly do this mod.

[GTOGEORGE]

Why are other racers going that route .............9/16" studs or studs made out of better materials (L19 or H-11) in high boosted engines. In my opinion it's better to have it and not need it then to not have it and NEED IT.......... 9/16" casted into the blocks and heads.


GTO George

[Travis Q]

Originally Posted by taff2

bifurcated

Now you went and made me break out my dictionary. LOL!

[BruceWilkie]

Originally Posted by Elarson

A 9/16" stud on a wimpy head would be a negative, since you would just get more deflection & crushing of the head with a higher clamp load. Note that you would have to bore a bigger hole thru the head, further compromising it's column strength. The stiffer head with lots of meat around the bolt holes has to come first.

Different alloys of aluminum have different strengths, but their stiffnesses are pretty much the same.

Eric

Dart heads use 355 because 356 degrades at 200*f vs 355 doesnt begin to degrade until 300 degrees and has a slower drop off rate above 300 than the drop off rate of 356 above 200. IMO that is significant.

[Tom Vaught]

Originally Posted by GTOGEORGE

Why are other racers going that route .............9/16" studs or studs made out of better materials (L19 or H-11) in high boosted engines. In my opinion it's better to have it and not need it then to not have it and NEED IT.......... 9/16" casted into the blocks and heads. GTO George

Messing with your George: Because the Traditional Pontiac Engine (including the RA-V) NEVER had a 9/16" head bolt so it is "not allowed".

Just like you guys will not allow moving the Bore Spacing (so that you could properly put that 9/16" fastener into the Block and the Heads vs taking away more thin wall material in the head and block castings at the current locations with the existing bore spacing.
Tom Vaught

[GTOGEORGE]

Tom,
This must be one of you 14,000 post! LOL

You love talking nonsense.


GTO George