I have a 85 351w block that I want to run on the street. The block has been rebuilt & bored .020 once. I think it would need to go to .040 to clean it up.How much of a bore is too much for a mild 500fwhp 410 or 414w?
Depends on the year of the block. The only way to know for sure is to sonic check it.
I bet you could go to .030, unless you have some scars....
All good questions for a machine shop that actually has your block....