These S&S Cycle Super Stock cylinder heads are a direct replacement for original equipment heads on S&S Cycle 4" Bore V107 and V113 Engines for 1984-99 HD Evolution Big Twins. The 93cc modified chamber Large 2.000" intake and 1.605" exhaust valves and high flowing ports supply plenty of air for big inch engines. Compatible with cams with lifts up to .585". Machined with the S&S Cycle 4" cylinder stud pattern. (Not for stock crankcases). Polished finish. 93cc heads, .585" lift springs