My pistons are Diamonds using the typical 1/16", 1/16", 3/16" ring pack. Have been using Total Seal plasma moly rings, not gapless.
I'll be switching to whatever ring Diamond recommends me to run for nitrous.

CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax