Inverted dome (dish) utilizes radius tooling to eliminate hot spots. Manufactured using 4032 low expansion high silicon aluminum that is heat treated for tighter piston to wall clearance. Valve reliefs cut for oversized valves and most street/strip camshafts. Lower ring lands and thicker crown for increased durability. CNC machined ring grooves accept 1/16", 1/16", 3/16" thick rings (sold separately).