I have a 76 440 that's been bored .030 over. The pistons are flat and are about .17 in the hole. I do have a fresh set of 915 closed chamber heads with HP sized exhaust valves. The cam is a Comp Xtreme 274 and so far my Duster has gone 12.69 @ 105 in the quarter. I feel that's pretty good for an 8.1 to 1 motor.