Souped-up car (3,3)
'souped-up car' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for hot rod that I've seen before include "Car with souped-up engine" , "fast vehicle" , "Car radically modified to increase performance" , "Car modified for extra power and speed" , "Souped-up vehicle" .)
(Other definitions for dragster that I've seen before include "Fast car" , "Car adapted for acceleration race" , "Racing-car" , "Bike" , "Vehicle" .)