USVTA rules require Novak SS, Ballistic, Club, or Boss 25.5 motors. ROAR allows any brand 25.5 motor, but it's usually best to stick with Novak so you can race anywhere without hassles. When all brands are raced, the Novaks still win or do well. There is no magic motor.

There are still a few places running 21.5 motors, so you should check with the track where you intend to race.

The USVTA rules are here:

http://www.usvintagetransam.com/rules/index.html

Almost any 5000mAh 2s LiPo will do fine, since the motors draw so little current.

You'll get more answers than you ever wanted if you post your questions here:

http://www.rctech.net/forum/electric...-part-2-a.html