What is a shovel head?

Shovelhead is an unofficial slang term referring to Harley's large V-twin produced from 1966 through 1984 (Evo engine production overlapping starting in 1983). It is used to differentiate the head design after the previous "panhead" that looked like baking pans. If you sight down the handle of standard shovel, the top of the metal blade kinda looks similar to the v-twin's head as you look from the right side of the engine. It is a stretch, but a cool term to use. You might notice that the older smaller v-twin Sportsters starting in 1957 have a similar shovelhead look, but the term was not typically used and instead, "ironhead" was used. Before panhead was knucklehead and after shovelhead were blockhead and twinkie for similar reasons, but most people refer to post shovelhead by using official Harley terms: EVO (for evolution), Twin Cam for the latest version based upon cam redesign. These are all terms basically used to differentiate large V-twins by design eras. The latest V-rod v-twin is becoming known as the "metric", because it went watercooled like the Japanese bikes and also for it's use of more metric fasteners and more overseas parts.