Moly race rings and I’m pretty sure it’s a 320 grit but I’d have to check. I’ve only bought two in 45 years and I still have both. I had a 9 second TRW engine back in the late 1980’s that the bores were terrible. Like .011 terrible. Moly rings wouldn’t seal and I had to finish points so I ordered a broken ring pak from California and ran cast, cast rings. That engine ended up running 9.82 and lasted a long time. It was then that my buddy told me to get away from using oil on my rings and switch to transmission fluid and I’ve done so ever since. My engine is broke in without a dyno before my first pass down the track.
