Start with this video to figure out 3 and 4 shaft boxes (also incorrectly referred to as 3:1 and 4:1).

https://www.youtube.com/watch?v=rKz1rTDO2qY As for motors, the way I heard it, they're called 380 motors because they're 38mm long, but I'm not sure if that's accurate. Like so much else in this hobby, names get applied that don't really mean what you would think they'd mean. The measurements of motors and they're capabilities are no load RPM and torque measured in newtons or grams per centimeter. For info on motors your best bet is to study the info available at the Mabuchi site. They give charts that have specs,



and if you visit the page

http://www.mabuchi-motor.co.jp/cgi-b...AT_ID=rs_380sh

you'll find that the stock RS380 motors have a no load RPM of 18,000 and a torque rating of 119 g.cm (grams per centimeter, I think). By searching for spec sheets on different motors you should start to get an idea of the differences. Right now I'm looking for a short (360 maybe) motor can that has very high torque, but so far I'm not having much luck.

Erik has spent a great deal of time studying this subject so maybe he'll chime in with his suggestions for you. The bottom line is that I still have a lot to learn, like with so many other aspects of this hobby. Just one more reason I like it so much.

It sounds like you have what are known as black steel gearboxes and they probably have the stock 380 motors in them. Can you post some pictures?