All I've ever heard about Harley Davidson's Shovelhead engine is 90 percent negative. It leaked oil, manufacturing was sloppy, needed to be rebuilt after 30k miles, vibrates like a blender, etc. Harley Davidson manufactured the Shovelhead engine from 1966 to 1984, and even if the negative comments are true, the Shovelhead engine had fans and here is proof. When Harley Davidson discontinued the Shovelhead in 1984/1985 and introduced the new and improved Evolution engine, Shovelhead fans came out with the slogan "see no evo, hear no evo, ride no evo." The slogan appeared on many t-shirts and stickers.

Shovelhead t-shirt with the slogan "hear no evo, see no evo, ride no evo."