Machined smooth heads. MOS 2 Coating:. Draws heat through piston walls and out the bottom. Reduces heat and friction, for added power and longevity. Helps eliminate cold seizures, and increases durability. Hard anodized crowns. Hypereutectic Cast.

1989-1992 fits Ski-Doo Formula Mach 1
1991 fits Ski-Doo Formula Mach 1 X
1990-1991 fits Ski-Doo Formula Mach 1 XTC
1992-1993 fits Ski-Doo Formula Plus
1993 fits Ski-Doo Formula Plus EFI
1992-1993 fits Ski-Doo Formula Plus X
1994-1996 fits Ski-Doo Formula STX
1994-1996 fits Ski-Doo Formula Z
1994-1996 fits Ski-Doo Summit 583