really anything can be rat rodded but usually they are 20's thru early 50's or known as pre 1955. I have thought of rat rodding my street rod to save money, rat rods are cheaper to build than full blow street rods as they don't have A/C and no real interior. usually the 20's and 30's are known as the rat rods and the 40's and 50's are known as Baggers or Tail Draggers.
Rat Rod
here's a Bagger / Tail Dragger