These pistons are specially designed for forced induction and nitrous applications. Pistons include .310" pocket depths and precision CNC machined ring grooves that accept 1/16, 1/16, 3/16 rings. Includes: Pin #927-2950-15-51S (140g) Contact reduction grooves, Double Spiro Locks # 927-042-CS, Double Pin Oilers. Bore: 4.030 Stroke: 3.500 Rod: 6.000 Deck: 9.000 Price per piston.