Cloyes introduced the very first True® Roller Timing Set in 1970, and has led the timing industry in quality and innovation ever since. Sprockets are made from SAE D7003 ductile iron or induction hardened cast iron for unmatched durability. The Renold True® Roller chain features full roller action and superior strength. Rollers are made from high strength steel, which is rolled and hardened to exacting standards. This Original True® Roller Set remains the benchmark against which all others are measured. Original True® Roller Sets feature: Ductile Iron, or Induction Hardened Cast Iron Cam SprocketRenold True® Roller Chain with . 250 Diameter RollersBillet Steel, Induction Hardened Crank Sprocket with 3 Keyway's, Plus or Minus 4 degreesSets Matched at the Factory to Assure True Center DistancePit Stop USA offers Cloyes Original True® Roller Timing Chain Set - SB Ford 62-84 221-351W (- .010) 9-3135-10 at low everyday prices. Be sure to check out all of our products from Cloyes including Cloyes Timing Chains - Small Block Ford.