Originally Posted by slantzilla
What is the purpose of those grooves?


Quote
Contact Reduction Grooves
These grooves are machined into the top ring land above the top ring to minimize contact drag when the piston rocks over upon reversal. They add minimal volume to the crevice volume, and they also help resist detonation by disrupting flame travel into the crevice volume where pressure spikes might unseat the ring.

68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads