These engines, with their simple roots blower, produce an abundance of of torque, at low engine rpm.
If you compound that engine torque, through the transmission (First Gear) and the rear differential ratio, you’re going to require a taller tire. This is all simple multiplication…
Since a taller tire reduces axle torque (here we divide the above by the tire radius) we must recognize that the additional rear axle torque we found, via using the higher numerical differential ratio, we are now going to attempt to kill by using the taller tire.
If the taller tire is not used, ‘Wheel Spin‘ will be worse,
than before the changing of the rear differential ratio.