Well, due largely to the fact that parts are a little hard to come by, I'd recommend something around a 27t stock motor, maybe 17 turn brushed, at the wildest. A modern 27t stock motor is pretty wild compared to the stock motors of just 5 years ago.
thanks for the help guys, i got lucky and was given one when my high school closing down the machine shop and drafting building so now i have a little project