In our experience, the most important thing to consider when setting pinion angle is to ensure that when under load, the driveshaft will be as in-line with the pinion as possible. This usually requires an initial setting of negative 2° to negative 4° so that the pinion aims slightly at the ground. This setting is usually achieved with stock length upper and lower control arm settings. 90% of the traction bars we install are Mega-bites (we'll get into why in a little bit) and even the "seniors" which are fully adjustable end up with a proper pinion angle 9 out of 10 times right out of the box with HP's initial factory setting. To make certain your geometry is correct it's necessary to use a pinion angle gauge, something we do with every traction bar install.

Now, remember when we said Hupp was hard-core? Get ready for Rear Suspension 101. "From the factory, the Mustang rear suspension is similar to a four-link," Hupp notes. "If you replace the bushings with solid aluminum pieces, it will function exactly like a four-link. You can box the stock control arms and fit them with aluminum bushings, and that will work. But if you really want to optimize [the rear suspension], you need to re-set your pinion angle, which can be done with a slightly longer-than-stock lower control arm. Factory is about 0-2 degrees down; you want 4-6 degrees. For really bad street/strip cars, I would recommend using aluminum bushings on the lower control arms and hard urethane bushings on the uppers to provide some sort of happy medium." All of this, Hupp amends, is provided you strengthen and reinforce the torque boxes first.