Chevy BBC timing chain cover ? --A new polished aluminum timing chain cover kit for big block Chevys. Fits '66-'90 Mark IV - 396, 402, 427, 454. May require extra thickness gasket or pump shims with short pumps. Offered as a kit to make easy - includes: --Polished cast aluminum cover? --Gaskets. Double Roller 9 Keyway Billet Steel Timing Chain? --Chevy BBC 454 Double Roller 9 Keyway Billet Steel Timing Chain Kit (Brs/Brg) --Maximum Advance/Retard at Camshaft: 4 degree --Maximum Advance/Retard at Crankshaft: 8 degree --Camshaft Gear Attachment:3-bolt --Material:Billet steel.Thrust Bearing Included. --Fits for Big Block Chevy 396 454 496 502 engines Package: including all items in the picture Professional Installation is Highly Recommended (No Instruction Included)