These S&S^® CNC ported B3 cylinder heads are original equipment on S&S^® T143 engines. They are set up for 4.425" bore and are machined for the S&S^® 4-3/8" cylinder stud pattern. Kit includes front and rear head assemblies complete with S&S^® .650" lift valve springs, and 2.200" intake and 1.800" exhaust valves, head gaskets, base gaskets, exhaust gaskets, and head bolts. Wrinkle black powder coat finish.