Overview Reviews Product Description 556-121 Holley EFI Cam Sync Kit, +600/1.0 inch Raised Cam Specifically designed for use w/ JESEL and similar external, dry timing-belt, cam drive systems. Includes 3 wire hall-effect sensor (8-20 volts), anodized billet aluminum bracket, mounting hardware, mating connector, and stainless steel 1/4"-20 "flying magnet" screw w/ high-temp, rare-earth magnet. Product Videos Custom Field Product Reviews Write a Review Write a Review × 556-121 Holley EFI Cam Sync Kit, +600/1.0 inch Raised Cam Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Email * Review Subject * Comments *