I have the opportunity to purchase either a complete 1970 455 out of a buick electra, a 455 from a 71-72 Riviera GS. Or a 455 from a centurion. Which would be the best engine to build for street/stip applications. I can get these motors complete for $150 a piece.
From what I understand, the earlier 455s had better cylinder heads. The combustion chambers were smaller, which helped yield a higher compression ratio. In addition to the head differences, there were differences the pistons as well. After 1970, I believe the dish of the piston was increased, lowering the compression ratio to 8.5:1. On later blocks, the oiling system was improved. If I am not mistaken, passages were enlarged from 1/2" to 5/8". Is it possible to mix and match? If so, I would go for the 72 block and the '70 heads. Are you planning on doing a rebuild? Mind you, I am relatively new here. This is my first attempt at giving any real advice.
Hello. If you are going to run it, or use the foctory pistons, go with the 1970. Sometime in 1971 (correct me if I am wrong), oil passages started getting bigger from the factory, and maybe again in 1973? Not entirely sure. 1970 is the only year you got small dish pistons in a 455. Good luck.
I'd shotgun the 70 motor into whatever untill one of the other two is built. The 70 is a decent performer out of the box. All I'd do is a cam change and you got a beast. I'd then decide which of the other two is more suitible to rebuild and use the other for parts. The Centurion and Riv motors are pretty much the same for the same years as far as I know. As said ealier these motors are a little better block wise, but certainly not headwise. Don't throw the heads away though. They can still be made to flow. The only heads that are throwaways are the 75-76's. Unless they are really clean. Then they are good replacements to your fully ported heads that are on a car you want to sell. It was mostly the piston that got you the 10:1 comp. ratio and the 8.5:1 ratio. I think in 75-76 the ratio was 7.9:1 and that was due to the open chamber heads and the lousy pistons.
I was just wondering where you live that you have the options to buy 3 455's? I'm looking around here (Utah) and there don't seem to be any.
If your going to build one up, I'd check the numbers and see if the riviera GS motor is a stage 1, if so that would be a great start(also the oil passages were bigger '71 up). But like everone said for a drop in pick the '70.
