R-LOK Crankshaft Adapters and Pulleys allow for a modular system in which pulleys can be changed in minutes. More concentric than pin-drive or keyway systems, the unique R-LOK design reduces side loads on damper bolts (a problem on mandrel-type systems). Available for Chevy, Ford, and Dodge, these CNC'd anodized aluminum adapters feature weight reduction pockets that do not affect structural integrity.