It depends on the wheels you're using. But if you do the 8" standard wheels that come in the kit, if my math is correct, you should have a top speed of
10.9 fps using the free speed of 5310 rpm.
(5310rpm * 14/50 * 14/50 * 21/28 * 8in/12in * 22/7[pi])/60 seconds
For torque, you should have
29 ft-lb using 2 cim motors with the stall torque of 343.4 oz-in.
(2motors * 343.4oz-in * 50/14 * 50/14 * 28/21 * [5.208 * 0.001]{to convert to ft-lb})/(8in/12in * 22/7[pi])
I hope that helps.
If my math is wrong tell me, because this is the way that I use to calculate the fps and torque for my gearbox designs.