The torque at the wheels is what determines the rate of acceleration. The torque is determined by multiplying the rated torque of the engine at a given RPM by the gear ratios and then adjusting for drivetrain losses.

In some cars, the wheel torque curves for the different gears will cross. In those cases, for maximum theoretical acceleration, the driver should shift at the RPM where the curves cross. On the SHO, this isn't the case, as shown in the graph below.

Thus, to maximize acceleration with a stock 5-speed SHO, the best technique is to run the engine to redline before shifting. This will maximize the area under the torque curves, giving the maximum available rate of acceleration.