Description
If you’re running a stock chain drive on your Twin Cam, you’re leaving performance on the table. The S&S CYCLE HP103 gear drive eliminates timing chain lash and the looseness inherent to stock setups, delivering precise valve timing that stock systems simply cannot match. Combined with the ability to run higher cam lifts and a stronger power band between 3500–6000 rpm, this is the upgrade that separates serious builders from casual riders.
Installation requires professional-level fabrication—material removal from the gear cover, hydraulic press work, and careful clearance checks—but the result is a measurably more accurate and responsive valve train. This kit is engineered for 103″ and 106″ Big Bore Twin Cam motors and pairs perfectly with stock cylinder heads up to 10.2 compression when paired with appropriate intake and exhaust components.
- Gear drive design
- HP103 camshaft
- Chain drive elimination
- Increased valve lift capacity
- Tighter timing tolerances
- Reverses rear cam rotation
- CNC-machined gears
- Includes inner/outer bearings
- Gasket and seals included
- Requires professional installation
- Material removal required
- New valve springs needed (99–04)
- Stock heads compatible
- 103″–106″ Big Bore compatible
- 3500–6000 rpm peak power
- Made in the U.S.A.
- Increased valve train noise possible
