Item: JE Pistons, BBC 638, Bore 4.625, Stroke 4.750, Rod Length 6.700, Flat Top -7.3cc, 583 Grams, Set
JE Pistons 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 Vertical gas ports for maximum top ring sealCompression Ratio:
65cc 16.5:1 70cc 15.7:1 77cc 14.6:1Photo is for illustration purposes only
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