What Gears???

With a 4 speed, I wouldn't go too low. 4.10's are pretty low as it is. I tried 4.88's back in the day, and it never felt like the motor ever got to use it's torque to pull that gear. It rev'd up so fast, it was always time to shift. You aren't launching when you are shifting.

Then there's the whole traction thing. Can you hook up that much torque multiplication?