So i am in the market for a 350, i found one that I interested in but the guy swears its been bored 80 over. I was 99% positive that 40 over is max max max on these 350s. that true?

 

Depends on the individual block. Usually you can assume you'll get .060 out of them, but you need to check the wall thickness when you get that high. Boring a block out to .080 would be unusual, but not completely unheard of. Expect your selection of pistons to be limited at that size.

 

At that overbore would it be a good idea to get it sonic checked for sufficient cylinder thickness?

 

Absolutely. Assume that you'll never get another rebore out of it, in any case.

 

as plentiful as 350s are you are gonna be hard pressed to get someone in a reputable machine shop to bore a block 80 over

the guy you are dealing with is more than likely full of ish

tell the guy that you want to take the block to a machine shop and have it measured out

some people think that boring is cool. I would rather have a standard bore block than the 60 over block I have now.

 

I have a 350 in my garage thats bored 80 over. It's rebuilt a friend gave it to me and I dont know what to do with it