Track-Pro kits for coilover 1964-72 Chevelle, GTO, 442,A-Bodies drag race kit Part # TPK-6472H
Specifically designed for drag racing Global West offers tubular upper and lower control arm a with low friction bushings that allow the front end to respond quickly. The upper control arms also have built in more positive caster. These particular units have 6 degrees built in. Caster as you probable already know provides straight-line stability. A-bodies from 1964-72 never had enough positive caster available using the stock components. Even if you used offset upper control arm shafts in your stock arm, the best you may get is 4 degrees positive. I would say the average is closer to 3 degrees positive.
The lower control arms are designed to support a coilover shock and spring combination. This area must support the cars weight and handle wheel stands. The arm will except tee type mounted shocks such as QA-1, AFCO and others. The shock bolts on top of the lower control arm, not from underneath. The lower arm bushings are made from a low friction plastic. When bolted on to the car, the arm should fall to the ground. Yet! Even though the arm moves freely there is still no deflection fore or aft. This is a great improvement over stock or polyurethane bushings. Straight –line stability is improved automatically.
Let’s talk about weight. The lower arms are a trade off from stock. We are more concerned with safety then weight. The lower arm needs to with stand a tremendous load. The upper arms are considered followers and are made out of 4130. They do not hold the car up. The cross shafts are made out of aluminum. You will save 8 pounds over the stock units. All of the savings will be in the upper arms.
In conclusion: The upper arms will provide superior geometry, more caster, low friction upper bushings and weight savings. The lower arms provide strength and low friction bushings. The combination will allow the front end to snap up rapidly and do to the design will also not deflect. The front end will hold an alignment and be stable.