R&D Racing Cylinder Heads are an economical alternative to the standard milled OEM head. Our precision cast heads are superior in design and features. Exchanging your OEM head with an R&D O-Ring head will raise your baseline compression ration, which in turn will give you greater overall power! The R&D "B" (rec) head allows you to run 92-Octane pump gas, have increased power and throttle response with total reliability. The R&D "A" (mod) head is designed to give a higher compression ratio for engines with high port timing, running on high-Octane race fuel. R&D Triple Heads are a one piece cast Aluminum shell, with removable Billet O-Ring sealed combustion chambers.