JP Performance Single Roller Timing Chain Set Keyway Adjustable Needle Bearing Billet Steel GM LS Series 1950592 Holley's EFI Crank Trigger Kit EQ TCC294A Holley's EFI Crank Trigger Kit is engineered to provide an accurate crank speed & position signal to Holley EFI systems in the most demanding Holley Billet Aluminum Throttle Cable Bracket 20 112 JP Performance Timing Chain Sets are supplied with induction hardened and multiple keyway crank sprockets (which have the keyways index marked for easier timing) and balanced camshaft sprockets and a true roller timing chain They are machined from billet steel and turned for greater accuracy on CNC machinery