Originally Posted by MarkBurgess

Any advice from me will be based on brushless motor running on carpet. But it will be some help I'll bet!

A 3.5R brushless would be too fast in a 1/12th. The weight and tyres can't really cope with that amount of power, and even if you could gear it to last it would still pack a heck of a punch.

You'd find a 4.5R plenty fast enough in a 1/12th, and a match for your brushed motor. If you want something easy to drive and make duration with, then I'd recommend a 5.5R (either LRP/Nosram or Novak)...and they are quite quick too!!!

Have fun,
Mark