Webster dictionary says it is:

Automobile rebuilt or modified for high speed, fast acceleration, or sporty appearance. A wide range of automobiles may be called hot rods, including some of those used in drag racing as well as those used in recreational cruising. They may be composed of used or new parts. Some are intended primarily for exhibition.

John Force calls his 330 MPH ride a Hot Rod... Sure if you want to call it a Hot Rod go ahead and watch the eyes roll back and eyebrows raise. Im my world it would be a Customized Import.