Torque at Start

Hello all, total newbie here.

I am converting a Triumph Spitfire and considering Direct Drive connecting to the differential. I am having incredible trouble determining the amount of Motor torque necessary to move the car from a dead stop.
Calculus is long in the rear view mirror. However it seems there should be a way to calculate the necessary torque given a 1800lb vehicle, a wheel radius of 11.6" and a differential ratio of 3.89/1.

Can anyone help me out here?