Specifically designed for Naturally Aspirated 632 engines to fit the following cylinder heads: 12º Raptor, 12º Pro-Filer, Dart Big Chief 14º (program #'s 3815 & 384), Sonny Tru-Pro 14.5º, and Brodix PB1200. Precision CNC machined ring grooves are designed for .043 back-cut top rings, .043 D-wall 2nd rings, and 3.0mm oil rings. Compression distance and compression ratio calculated with zero deck clearance at listed block height.

Includes:
Pin #990-2930-18-51S (174g)
Double spiro locks (#990-042-CS) Rail Supports(# 4600-203)
Double Forced Pin Oilers, Accumulator Grooves, and Vertical gas ports for maximum top ring seal