Man, I must have read another thread? From what the poster says, he is doing not much more than a stock 440 hp motor. He has a little cam, a dual plane Performer intake, not the rpm. He does not know his compression ratio yet, but if he had bought some 5-600 dollar pistons, he would probably know about it and what the comp ratio is supposed to be. He has good heads and rockers and was probably going to use manifolds and you guys really think he needs an 850 or 950 to feed maybe 400 horses? Sounds like a recipe for a slug to me, but, hey, I am just reading what HE says he already HAS and is going to use.