they run on-road..
the main class is VTA...which is old school American muscle cars with spec motor Novak 25.5....
here are the rules...
http://www.usvintagetransam.com/index.html
the FDR is final drive ratio...that is set at 3.5...you cant go lower than 3.5 like 3.4,3.2...ect...on-road chassis get this number by what chassis you run...for example...I run a Associated TC3 with a internal of 2.5...I take the spur divide it by the pinion and multiply by the internal...and that gets me my FDR...
68/48x2.5=3.5 FDR for my TC3
TC is touring car, which runs a 17.5 motor in stock mode or blinky, the esc must be set to this. The bodies are more race type style