What is your 392 out of? The lowest compression for the 392 was 9.25 and the 58 Chrysler Imperial was 10 to 1. So a good place to look is what was in there in the begining.

10 to 1 is a easy goal to shoot for in a 392. There was more stuff made for them and there still is a lot of parts still floating around for this motor. It and the 354 are probably the two easiest early Hemi's to find parts for. A couple of the piston manufacturers may have a set or two on the shelf or may be willing to whip a set up. Egge Machine certainly will custom make you a set or the may "Just" may have a set of NOS pistons to fit your target build. Going with NOS would be the easiest on your wallet. When I built my last Desoto Hemi a 330 inch motor I had Egge make me a set price wise-- $204.87 each. Like I said nothing cheap about building one of these motors....

Roland