O.S. Engines 45904110 Cylinder Head for FS-91-P Engine FEATURES: Aluminum construction Pre-installed brass tubing guides for the valves INCLUDES: One FS 91 Surpass Pumped Version One Aluminum Head Gasket COMMENTS: For cylinder head with valves pre-installed, use OSMG5232; The intake ma INCLUDES: One FS 91 Surpass Pumped Version One Aluminum Head Gasket COMMENTS: For cylinder head with valves pre-installed, use OSMG5232. The intake ma