To make a long story short, I have a 454 out of a 90 suburban Im going to use for the powerplant in my 68 Chevelle restoration. It has been punched out .040 already and it has a piston with the top of the ring groove broke off about an inch and a half. My question is. What are the largest oversize pistons I can get for it. I know I can get a .060 over and surely it will clean up in .020 thou but if it dont I am looking at other options. Thanks

I've gone .125" over, but we sonic checked the cylinder walls to make sure it would handle it.

Honestly, its been my experence that the late '70's and newer blocks have thinner cylinders and won't handle more than a 0.060" overbore.

Sonic checking is the only way to know for sure.

Hope this helps.

I was gonna say the same thing...my machine shop said they go .125 over all the time on older MkIV blocks, but you have to sonic test it to be sure.

If its already .040, I wouln'nt think twice about going .060. That is only .010 more off the wall thickness.

I have bored dozens of 454s .100 over with no problems. The engine in my camaro now is a 505 which is a 454 .100 over and 4.250 stroke. I got the block for free because it had a worn out .060 bore and the owner was scrapping it. Now it makes 600hp(I think, I'm going to rear wheel dyno it as soon as I can get a trans to hold up behind it)