jerry is right we use to go 0.60 to build a 292 and if we found a good block and punch them 1/8 to 4 in. that's a 301 and they really did run when they were cold but when the got hot and they really did have heating problems but a lot blocks didn't survive so jerry is right use a 4 in. block but I would try to find a 327 block and put a 283 crank and build a screeemer that's what chevy did in 68 with the z28 302 that turned out to be a legend.....ted