[lincpimp]

I would first decide what battery and esc you will use. This will determine what motor (kv) you will need. I would say that the 42-40 looks good, but at 900kv ma be a bit too fast. Overall truck speed of around 40mph is good to aim for. Much more and it becomes difficult to drive. Also keep in mind that your only method of altering speed will be changing tire height. You may be able to change the diff ratio, I ma not too familiar with the e-savage. Generally a longer stator will offer more torque than a shorter one. And a smaller diameter motor will spin up faster than a larger diameter. The 40mm (or so) diamter outrunner seem to be the best choice for a 10th scale mt direct drive setup. Most have 6mm shafts, as do most center driveshaft, like the revo sliders, so installing them is easier. Also motor weight is a consideration, as JRH mentioned in another thread. A lighter motor is not necessarily a good thing for this application.

To sum it all up, a good match of battery, esc, and motor is required and more though is required to get this. Not as easy as just picking something and figuring out the gearing to make it work!