New Manley Forged 13* Pistons. 4.125 Bore with 1.125 Compression Height/Compression Distance. Pistons have a -13 cc dish. Pistons use an .043 x .043 x 3mm ring package. Set up for .927 diameter 2.750 length wrist pin. Package includes Groove lock Spacer rings ( oil rail supports) and .073 wire pin locks.