The Shovelhead is an air-cooled, 45 degree, V-twin

V-twin

A V-twin engine is a two-cylinder internal combustion engine where the cylinders are arranged in a V configuration.- Crankshaft configuration :Most V-twin engines have a single crankpin, which is shared by both connecting rods...

 motorcycle

Motorcycle

A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...

 engine

Engine

An engine or motor is a machine designed to convert energy into useful mechanical motion. Heat engines, including internal combustion engines and external combustion engines burn a fuel to create heat which is then used to create motion...

 manufactured from 1966 to 1984 by the Harley Davidson Motor Company

Harley-Davidson

Harley-Davidson , often abbreviated H-D or Harley, is an American motorcycle manufacturer. Founded in Milwaukee, Wisconsin, during the first decade of the 20th century, it was one of two major American motorcycle manufacturers to survive the Great Depression...

. It has 1208 cc of displacement and, after 1978, was increased to 1340 cc for Harley's Big Twin bikes.
The "shovel" cylinder head represented an offshoot of the panhead design it replaced in 1966 but featured a slightly different look. The name was derived from the appearance of the rocker box covers. Because these covers bring to mind the head of coal shovels when inverted, the name shovelhead was a natural progression. The shovel engines powered Harleys up until the introduction of the Evolution engine in 1984, ending the reign of the "shovel" as enthusiasts frequently call these engines. The shovel engine does not have covers, per se, but rocker boxes and rocker arms which pivot on shafts. The design provided more than a unique look; it produced 10% more horsepower than the panhead engine which it replaced. From 1966 through 1969 the shovelhead kept the panhead style lower end. These early style shovelheads with the generator bottoms were often referred to as slabside shovels. From 1970 on the shovelheads used an alternator bottom often termed a cone shovel.

A number of third-party engine manufacturers produce custom Shovelhead-style engines, in a variety of bores, many much larger than the original design displacements. Each manufacturer includes upgrades to the original design to improve the performance and reliability while still providing the original styling and overall engine structure.