Does anyone know that tolerance spec for older SBC 265/283 for cylinder bore? Somewhere I thought I read .008 as a max difference. Any engine builders with opinions please chime in. tks.
I had read your earlier post about using a 265 engine. My plan was to use a Canadian, 4 bolt main,305 block bored .014 over to standard bore 55-57, 265 specs, use a large journal (I don't include 400's in sj/lg notation) 3" stroke crank (68-69, Z-28, 302 or aftermarket). The idea was to build a stout bottom end with a small CID engine (265). But, that all fell apart when my Canadian,4 bolt, 305 block was missing the main caps, had a DEEP ridge, and was rusted BAD; my "standard" bore forged 265 pistons would up being semi-finished (and far too expensive to have them finish ground, 4-8 hundred dollars); and my 1178 crank got sold out from under me (he who snoozes, loses). I have'nt given up yet because I have the different intakes (single and dual quad), and a just finished pair of 265 Power Pack heads. Stock style, cast, 265 pistons are still available, and a 265 will go to 283 bore safely. You can get forged pistons from the aftermarket, but you'll PAY. My 59 edition MOTORS MANUAL says anything over .005 should be bored. Butch/56sedandelivery.
If it has any taper, it's gonna wear out the rings kind of quickly. How much is allowable, depends on how long you want it to last. 8 thou might be good for 10k miles, maybe not.