From 1966-1984 HARLEY DAVIDSON built the SHOVELHEAD engine.This engine is named for the design of the inverted scoop-shaped valve covers.By doing  this harley increased its horse power by 10%.The shovel head motor is similar to the sportster engine except it is a big twin with an independent transmission.The original design was a 1208cc (74 cu in) of displacement.In 1978 this was increased to 1340cc (82 cu in)of displacement.Early shovels with generator bottoms were called slabside shovels.1970 brought about the alternator bottom they were called cone shovels.