[Tom Vaught]

Originally Posted by slowbird

Haven't read all the post so not sure if it's been said, Ford runs 4 head bolts and they hold up good. 5 is better but 4 will do fine.
The number of head bolts isn't what causes Langer to replace head gaskets every 25-35 passes it's heat from the paired exhaust ports. The end cylinders are happy and could go a A LOT longer but the center cylinders just can't deal with that heat in that area

Have to agree, Brian, totally with that observation.
The center cylinders head material sees twice the heat cycles of combustion from the paired exhaust runners.
With most engines, ideally, you would have have each runner see one heat cycle in 8 firings. In the case of the Pontiac,
4 cylinders are seeing that double heat cycle. 3 and 5 on the drivers side and 4 and 6 on the passenger side.

50% more heat per engine combustion engine cycle than necessary vs using the Ford or RA-V exhaust design.
AND the Pontiac Engineers knew of the issue in 1967 and earlier, when they were doing the initial engine work on the RA-V engine.

Tom V.

[pastry_chef]

Originally Posted by John Langer

The head bolts are in the wrong place. There isnt enough material between the center combustion chambers, There isnt enough head bolts for the bore spacing.

Bore spacing vs head bolts, interesting.

[slowbird]

Originally Posted by pastry_chef

Bore spacing vs head bolts, interesting.

Hate to argue with Langer but Warp6 heads and RA5 heads don't burn the centers out of head gaskets, kind of points back to the paired exhaust ports and heat.

[pastry_chef]

Originally Posted by slowbird

Warp6 heads and RA5 heads don't burn the centers

The split exhaust ports help for sure, but how many 1250 HP plus Warp6 or RA5 heads lay down regular passes at the track? None.

[slowbird]

Originally Posted by pastry_chef

The split exhaust ports help for sure, but how many 1250 HP plus Warp6 or RA5 heads lay down regular passes at the track? None.

I think bossbird would expose head gasket issues on ra5 heads by now. Nitro seems to find the weak link. And again if it was head bolt related why doesn't anyone ever blow out the end cylinders? Why is it that the gasket fails between the center cylinders right where the exhaust valves are everytime and no place else? Why when adding better cooling to that area do the head gaskets last twice as long? To me that all points to heat not a head bolt issue.

[pastry_chef]

Bossbird, the billet head is a different animal it seems.

Originally Posted by mgarblik

Believe it or not, we are still on our first set of head gaskets from 2011!. 10 head studs, 9/16". The secret is the solid, billet head. Thick and uniform around the studs, Eric did a wonderful design job leaving lots of clamp column around each stud. It's clamped down tight and doesn't move.

[slowbird]

Originally Posted by pastry_chef

Bossbird, the billet head is a different animal it seems.

No extra head bolts, they are located in stock location. I agree they're a different animal

[242177P]

Originally Posted by slowbird

Hate to argue with Langer but Warp6 heads and RA5 heads don't burn the centers out of head gaskets, kind of points back to the paired exhaust ports and heat.

Pretty sure you're both on the same page. Here's the entire post, because context. Note CENTER combustion chambers.

Originally Posted by John Langer

Pontiacs are junk, I dont know why anyone would ever want to try to build a serious race engine out of them. The bore is too small, the strokes are too long. The deck heights are too tall, the valve train geometry is whacked. The push rods are too long. The head bolts are in the wrong place. There isnt enough material between the center combustion chambers, There isnt enough head bolts for the bore spacing. The cranks are too heavy, the main and rod journals are too big. The cooling system is junk. the oil system is junk. The only good thing about them is that you dont have to pull the distributor to change the head gaskets every 7 passes. When I was making under 1000 hp head gaskets would last around 35-40 runs, under 1070 runs 20-25 runs, under 1090hp 10-15 runs, 1117hp, they leak after warming the motor up. A maximum effort Pontiac will never be able to compete with a maximum effort bbc. If I destroked my motor to 500" and put a dry sump on it and 2 dominators I think I could make close to 1100hp. NHRA pro stock BBC's make over 1430hp at the same displacement. That gap will never be closed!