The Shovelhead engine is a motorcycle engine that was produced by Harley-Davidson from 1966 to 1984, built as a successor to the previous Panhead engine. When the engine was first produced, the Shovelhead had a shallower combustion chamber, larger valve drop for both intake and exhaust, better porting, and stronger valves and pistons. This gave the new engine an extra 10 horsepower, along with a different appearance.[1] The engine gained the nickname “Shovelhead” because its rocker covers look a little bit like an upside-down coal shovel.[2] While the engine did have problems, it gave Harley-Davidson a 26% sales increase during the early part of its timeline