GM has filed a patent application a variable displacement valvetrain system with rocker shaft porting and insert sleeves for engine cylinder deactivation.

Pushrods convert the vertical motion of the lifter from the camshaft lobe into valve movement. A V8 engine takes advantage of that by centrally locating a single camshaft in the middle of the engine ...

Overhead cams are a more efficient method of actuating the valves than with a pushrod, but someone in Detroit never got the memo. And thank goodness they didn't. With production pushrod mills turning ...

The debate over the optimum rocker arm ratio to use has dragged on probably since the invention of the pushrod V-8. Even though Chevrolet made the decision easy for us when it engineered the original ...

The rocker arm employs the use of a fulcrum or pivot to increase the cam lift by a given ratio. That increase in lift is the result of moving the pushrod pivot point closer to the fulcrum. That ...