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: 3.750 Rod: 6.000 Deck: 9.000 Price per piston.