High compression. 883-1200 conversion piston set. Compatible with stock unmodified cylinder heads. 10:1 Compression ratio. Piston weight 335gr. Piston pin diameter .792″ and weight 97gr. Head type: Dish. Dome +10cc. Compression height 1.210″. Bore 3.498″. Stroke 3.812″. Rod length 6.926″. 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. Note: 1200cc cylinders must be purchased for 04-up 883 XL models. Stock cylinders liners of 04-up XL models are too thin to bore to 1200 size.