My father was a chevrolet mechanic/machinist. We got a deal on a boring bar from a tractor dealership/ to put a sleeve in a dump truck. Hotter than haites, but we did it , I was just a kid. Well , we kept that ole boring bar around, and we stumbled onto this car, and a truck motor from a salvage yard that my dad had exchanged back in the day. When the 454 came out, in trucks, people were'nt ready for the horrendous mileage. Anyway, we bored the motor .030, and all the cylinders measured within .0005 with that old boring bar. If you're gonna build a big block, build it tight, if you want it to live.