These S&S® Super Stock® cylinder heads are a direct replacement for original equipment heads on S&S® V107 and V113 4" bore engines for 1984-'99 HD® Evolution® Big Twins. The 93cc modified bathtub chamber is designed for a flat topped piston. 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 .650". Machined with the S&S® 4" cylinder stud pattern. (Not for stock crankcases). Wrinkle black powder coat finish.