I have to bore out my 430, it’s already 30 over. If it’s bore me out further will it basically be a 455 at that point. I’m trying to determine if I can fit forged 455 pistons in. Thanks
The 430 is standard @ 4.1875 4.2175 @ .030 and 4.2475 @ .060 The 455 is standard @ 4.31 So you would have to go another .090 over what you now have to get to 455 pistons. You can go to .060 (4.2475) on your 430, and be fine. The 455 is not a 400/430 block bored to a 455. (although some people will tell you that). The 455 has thinner webs and areas to reduce even more weight that the 400/430s. There are some new "old stock" .060 TRW pistons for the 430 available, or you can have custom forged pistons made. As the boss stated above, get the block sonic checked for core shift and MPI for cracks. Then decide on pistons. The cost of the custom might be half again or double the TRWs, but if you go with custom, you can have the compression height and other things factored in rather than having to work to the pistons specs.
Are you currently running a forged pistion or cast and how much needs to removed to clean up the worst cylinder Bores?
