.60 overbore on a 1968 340
Thanks guys, I've since taken the block to 2 other machine shops for second opinions. One said the cylinders are fine, they just need a bit of honing, and the motor would be fine for the driving I will do with it. The other was on the fence about whether it need boring or not. I also found a lead on an original 1970 340, rusty but never bored for 350.00. This may be the ticket.