Crane Cams Pro-Series Steel Billet Gear and Roller Chain Sets Offer The Precision, Strength and Accuracy Of Billet Steel, Nitride Hardened, CNC Machined Camshaft and Crankshaft Sprockets With The Strength, Friction Reduction and Wear Resistance Of a Premium Quality, German Manufactured, Double-Row, Roller Timing Chain. The Billet 4140 Steel Nitride Hardened Crankshaft Sprocket Features Nine Separate Keyway Locations, Providing Up To Eight Degrees Of Advance Or Retard. Note: Due To The Increased Width Of The Sprockets and Chain, Clearance Must Be Checked Between The Timing Set and The Block Casting. Some Applications May Require Minor Grinding Of The Block For Clearance. This Product Is Applicable Only To Pre-1966 Califonia and Pre-1968 Federally Certified Passenger Cars. It Is Also Applicable To Non-Emission Controlled Trucks and Similar Vehicles. It Is Not Applicable Or Intended For Use On Any Emission Controlled Vehicles Operated On Highways Or Roads. (Complete Set With Multiple Keyway Crank Sprocket and Machined To Fit Supplied Thrust Washer).Pit Stop USA offers Crane Cams Pro Series Steel Billet Timing Chain Set - Ford V-8 73-00 255 (4.2L), 302 - 302 H.O., 351W, 351 SVO 44984-1 at low everyday prices. Be sure to check out all of our products from Crane Cams including Crane Cams Timing Chains - Small Block Ford.