Crow single and double row billet steel timing chain sets are the ultimate in strength, timing accuracy and long term durability. The new Crow Timing sets now feature a German IWIS brand timing chain for much greater resistance to chain stretch and breakage. Precision CNC Machined billet steel top and bottom gears Induction hardened crank gear for exceptional wear resistance on gear teeth Nine keyways broached on crank gear in one pass with one tool to insure timing accuracy 6 cylinder gear have 7 keyways German quality IWIS true roller timing chain