These Manley timing chain sets are designed to provide consistent, accurate timing for your high performance engine. They feature fully machined billet-steel camshaft and crankshaft sprockets, a full double-roller chain using .250 in. diameter rollers, and a 3-keyway crankshaft sprocket. Manley timing chains use camshaft sprockets that are machined for and include either a brass wear shim or Torrington thrust bearing. Keep timing stable and accurate throughout the entire rpm range with these Manley timing chain sets.