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The info on the catalog page does a good job of detailing the features and benefits of our GM tubular control arms. We have been producing these since 1991, with hundreds of sets installed and proven. In fact, our ’70 Chevelle ran them in the in the 2008 Super Chevy Suspension challenge, putting in times consistent with a new production Corvette…and with an iron Big Block and street compound tires! We feel that urethane bushings can provide more precise handling due to less compliance than seen with OEM rubber bushings, but with that same advantage creating a harsher ride in the real world of patched pavement! We use urethane bushings on top for the greater control, but normally supply OEM rubber bushings on the bottom to make the ride more livable. Lower urethane bushings are a no charge option if you prefer them.

Our molded urethane lower spring seat is also an advantage in transferring less noise and harshness than OEM and competitors arms which mount the springs in a steel to steel fashion. That seat is bolted in place and is easily removed for the use of Coilover and Airride conversions.

Speaking very frankly, the major advantages of tubular control arms are a better cosmetic appearance, an optional narrower track width for tire clearance, and the use of better alignment to match modern speeds, radial tires, and power steering. Tubular arms are not appreciably lighter than stock stamped arms, although they do deform less under heavy cornering loads, which can lead to more predictable handling. The narrower arms were first produced for street rods that had a too wide subframe installed, and need extra tire clearance. The Pro Mod guys then started using them for the same reasons on their cars with the OEM suspensions.

All our tubular upper control arms have modified upper ball joint positions which arrived at by testing on multiple cars. We typically move the ball joint to the rear to allow more positive caster settings than are available with OEM stamped arms. Ball joint angles are optimized for lowered cars, and in some cases we have altered the control arms length for better camber settings. We also make our billet steel upper control arms shafts with a 3/16” offset, as pioneered by the MOOG company “Problem Solver” line of upper arms shafts. The GM frames seem massive, but have proven to sag in normal use. The 3/16” offset in the shaft allows the alignment technician to effectively alter the length of the upper arms by 3/8” (3/16” times 2, since the offset reverses to double the effect). This allows modern caster and camber settings without huge shim stacks that can slip. Since we know we are dealing with custom cars, we can build customs arms to solve ball joint angle, alignment, and wheelbase problems…usually at no extra cost!

We have stayed with 1” x .188 wall DOM steel tubing, rather than the larger OD tubes seen in competitors control arms. The engineering fact is that a larger OD, but thinner wall tube is not any stronger. And the larger diameter makes some of the necessary clearances more difficult, requiring those larger tubes to be mashed flat to be welded to the bushing and ball joint bosses. We would rather use the size tubing that allows an undamaged tube to be welded to those critical areas.

We normally coat our control arms with a lacquer primer, which readily accepts acrylic enamel finish paint. The acrylic enamel is one of the more impact resistance type paints and will resist chipping quite well. And it can be sprayed in a color that complements the paint scheme of your entire project car. We do offer a powder coating option which is unique in that we offer a wide choice of colors. It is often difficult to truly match a powder coat color to normal paint, so we would suggest a coating color that is an accent color instead.

Chevelle Parts

Fatman exclusive G-Tech spindle is a really important improvement for the 67-69 Camaro, 68-74 Nova, and 64-72 Chevelles. A 2' drop is accomplished, with the strength of a one piece forged spindle. The taller spindle geometry was pioneered by Penske/Donahue back in the early days of Trans Am racing. The greater height makes the camber curve lean the tire into the turn, rather than out as stock. The upper arms must go down hill toward the center of the car to accomplish this. The new control arm angle also raises the chassis roll center in relation to the center of gravity. This reduction in the roll couple results in flatter cornering and less need for monster anti-sway bars that may increase ride harshness. A look at any Indy car will show you a level lower arm and the center inclined upper, which is the accepted form for superior handling. The taller spindle is also an advantage for drag racers as it allows more down travel for suspension during launch. Understeer is greatly reduced and results in a tested 20% improvement in cornering power. We also positioned the upper ball joint tapered hole so that either stock or tubular control arms will align properly. (This taller spindle geometry works so well that GM used in as standard on the ’73-77 cars, which have excellent design from the factory.)

When the actual prototype parts were installed on a car, we did a bumpsteer analysis and found that the steering arm position needed an adjustment to dial in the geometry. We included that advance in our final design. No other spindle on the market, taller or not, can boast this improvement born of real testing real cars!

Some vendors still sell dropped spindles for these cars that use Metric GM disc brakes, but that is a step backwards in terms of stopping power. The rotor is smaller than the stock Camaro unit, and the caliper has a smaller bore and pad for less clamping force. Our G-Tech spindle will accept any disc kit we’ve seen for stock Camaro spindles, from stock iron to Wilwood, ECI, Aerospace, and Baer. A small trim of the caliper bracket is usually needed on the ¼" thick stamped caliper bracket used with stock GM disc brakes. Install these G-Tech dropped spindles in a couple hours on a Saturday morning, without even needing to rebleed the brakes. A quick trip to the alignment shop and your GM Musclecar's handling and stance will be transformed!