The Harley-Davidson Twin Cam engine succeeded the Evolution engine in the company’s Big Twin motorcycles.
Harley-Davidson introduced the Twin Cam for the 1999 model year. Its name refers to the two camshafts used in the engine, unlike the single-cam arrangement of the preceding Evolution Big Twin.
The first version was known as the Twin Cam 88 because it displaced 88 cubic inches, or about 1,450 cc. Later versions included the Twin Cam 96 and Twin Cam 103, which offered larger displacement. The engine powered many Touring, Softail, and Dyna motorcycles.
The Twin Cam is distinct from the liquid-cooled Revolution engine used in the V-Rod and from the later Milwaukee-Eight engine. It remained a central Harley-Davidson Big Twin design until the Milwaukee-Eight began replacing it for the 2017 model year.