Designed to provide even greater increases than World Products' own Sportsman II heads, the Motown 220 cylinder heads rate as the ultimate small Chevy cast iron heads. Features include high-tech 64cc combustion chambers, 220cc intake runners capable of excellent flow and velocity, high-flow ports, and standard 2.055 in. diameter intake valves. They're ideal for large-displacement small blocks (383 or larger), and are available in bare or complete assemblies with valves, retainers, screw-in studs, guideplates, and your choice of 1.440 in. or 1.550 in. valve springs.