If you use the 292 I would stay away from a flat top pistion as this can end up putting you into the 11-1 PLus compression Range. But for Either motor. I would try and keep them at 10-1 or just under. When you starting getting Past the 10-1 compression mark You WILL also start needing Much better fuel Then what is at your Local Gas stations. You should also think about stepping the cam up on this rebuild. A few reasons here But Biggest reason being better performance. Like something with a 110-114 lope sep.,lift in the 450-550 range, & rpm power band range of just off idle to the 5500-6000. If you let me know what type of gears & tranny you plain on useing I can list or send you some good choices/ideas. hope this helps }[oooooo]