for Twin Cam

Engines of the Twin Cam generation respond extremely well to performance cams due to their larger bore and shorter stroke. Significantly more torque and horsepower are within easy reach. The cam sets work in carburetor and EFI engines. Stock hydraulic tappets can be retained but OEM  non-adjustable pushrods have to be swapped for adjustable type pushrods.

The S&S 510C camshaft set is designed to be used with the stock H-D chain drive system and is an economical way to improve the performance of stock and slightly modified street engines. The S&S 510C cams are as quiet as stock but produce significant power increases across the rpm range, especially above 3000 rpm. The 510C cams are compatible with the stock splined chain sprocket used in 2000-up Twin Cam engines, but may be used in 1999 engines if the H-D 2000-up style splined rear cam sprocket is used. S&S’s 1999 FXD test bike produced 62 horsepower in stock con-figuration. Horsepower jumped to over 82 with 88 ft-lb. of torque after the installation of S&S .510" camshafts, adjustable pushrods, an S&S Super E carburetor and air cleaner, 6200 RPM Screamin’ Eagle ignition module, and S&S slip-on mufflers.

Timing chain or gears? That is here the question. In High Performance engines S&S Cycle prefers gears so their camshaft design for the Twin Cam models features new gears which replace the stock chain drive, sprocket and tensioner system for the cams. While being only slightly noisier than a chain gears incorporate some very important advantages:
increased timing accuracy by eliminating chain lash, almost zero wear compared to a chain, no wear particles in engine oil from tensioner & guides, absolutely safe operation, gears cannot fail and tear,
The latter is a very important factor with the installation of high lift cams and strong valve springs.
S&S Gear Drive camshafts are sold by W&W as complete kits which consist of two camshafts with pressed-on inner drive gears, two outer cam gears, cam bearing plate, four bearings, small parts and gasket.