S&S® Super Stock® 91cc Cylinder Heads For For S&S® T-Series Complete Engines and 1999-'05 HD® Big Twins With S&S® 4-1/8" Bore Hot Set Up Kit - BlThese S&S Super Stock high performance cylinder heads are designed specifically for S&S T Series complete engines and 1999 '05 engines with S&S 4 1 4" bore Hot Set Up Kit installed. 2. 000" intake and 1. 605" exhaust valves coupled with S&S ports, supply plenty of air for these big motors. Not machined for S&S compression releases. The manifold mounting surface is machined to stock dimensions, so a special manifold throttle body is required for