The Revolution engine is based on the VR-1000 Superbike race program, developed by Harley-Davidson's Powertrain Engineering with Porsche helping to make the engine suitable for street use . It is a liquid cooled, dual overhead cam, internally counterbalanced 60 degree V-twin engine with a displacement of 69 cubic inch (1,130 cc), producing at 8,250 rpm at the crank, with a redline of 9,000 rpm. It was introduced for the new VRSC (V-Rod) line in 2001 for the 2002 model year, starting with the single VRSCA (V-Twin Racing Street Custom) model. The Revolution marks Harley's first collaboration with Porsche since the V4 Nova project, which, like the V-Rod, was a radical departure from Harley's traditional lineup until it was cancelled by AMF in 1981 in favor of the Evolution engine.