sbc 350 swap
400 hundreds by chevy aren't even like chevy. The connecting rods are short, the engine is a small block. The short rod throughs the piston more heavily into the thrust side wall. Scrap it fast as possible. The only real reference to small block pontiac is crankshaft journal diameter. There is no small block. Parts are expensive. A 455 definetly redlines at 5700. The connecting rod bolts break. That is always the case. None hold at 7000. 3.75 stroke. But it is a torque engine however. What is your rod length on the stroker. What I ask before anything is what is the rod to stroke ratio. What is the rod length center to center,vs; stroke. 1.83 like 426 Hemi is good number. AS you get closer to 2 the engine doesn't have enough vaccum to draw fuel in. It has to have a blower of some sort. Pontiacs all are long stroke. One of the magazines years ago did a article on 455s . 425hp at 5000 rpm.Don't get funny itwill break. Theyused heads off 72 and 73 gto 400's. Gives 10.0 compression ratio. Then you have to cam it. In a transam with a 2.50 differential ratio ford axle, the only place to get 2.50 diff, they were running a TA at 160 mph Of course the distributer, carb jets, and size all had to be tuned together,Not to tough. Pontiac never messed much with their heads. They knew that they could not flow at 7000 anyway. The head casting numbers are on the middle section of the head 7k3 and 96, if I remember correctly. I will take the 455 myself. But I have said about what every one else has. Pontiac is what I do, I will take the 455. I need another one. I don't have a clue on the heads I am the only persion I know who has a set. If I did not have a huge pile of parts, I would never start with pontiac. It is just to expensive. The parts are dissapearing, the people that know much are going, chevy still moving on.