Standard replacement piston set for stock applications. Stock 9.0:1 compression ratio. Piston weight 341gr. Piston pin weight 97gr. Head type: Flat top / Dome +1.5cc. Compression height 1.210″. Bore 3.498″ / Stroke 3.812″. Rod length 6.938″ / Cyl. length 4.650″. Comes with T6 heat treated 390 Hypereutectic cast pistons with 16% silicone levels which enables running a very tight clearance for longevity and hardly any piston noise. Note: Top compression ring will need additional clearance. See instructions.