Cylinder Head (LS1 Showroom Stock Racing)
This uses a production LS1 cylinder head (casting P/N 12559853) and has .035" machined off the deck surface to decrease it to 63cc chamber size. This raises the compression to 10.8:1. They also do a performance valve job with CNC porting with high lift valve springs P/N 12565117. Includes valves and springs.
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