Revo tanny ?

[JB3231]

I'm in the process of ordering all of my parts for a Revo 3.3 brushless conversion. I have decided to use the stock Revo tranny and chassis and order the motor mount from Mike.

It looks like I need a mod1 5mm pinion to use with the Revo tranny spur. I'm using a MM esc, Feigao 9XL, and 4S. Could someone give me a heads up on which pinion to order, or at least a good starting place. I'm going to lock the tranny in 2nd. They are too expensive to order alot of them just for trial and error.