Installing TRZ Drop Spindles and Aerospace Brakes On Our G-Body

Bet you thought our ol’ Grandma up and died, didn’t you? Well rest assured, she’s alive and kicking. But rather than baking pies and attending Bingo nights, our Grandma — Project Grandma that is — has been tucked away in the Power Automedia garage awaiting the next stage of her tire-roasting life.

With more projects ongoing than we can shake a stick at, and some of those projects partially intertwined with another, Project Grandma has been on the backburner, so to speak. But she recently drug out of her extended slumber and put back into the limelight out in the shop for a few changes in the suspension and wheel department. Before we move on though, let’s take a look back.

Here's the complete setup going on Grandma, including the Aerospace disc brake setup and TRZ Motorsports drop spindles and billet steering arms.

Project Grandma, a ’78 Chevy Malibu, has been one of Power Automedia’s longest-tenured project cars, working her way from a dilapidated street cruiser to a 10-second strip warrior. Along the way, Granny got a complete 25.5 spec cage and all the best parts and pieces we could outfit her with. At the heart of it all was the Pat Musi/Edelbrock 555-inch big block Chevrolet powerplant that initially was nitrous-fed but later set up for low compression and mated with an F2 ProCharger.

Granny’s Back From The Dead

As she was, Grandma sported a front brake kit from Aerospace Components, complete with 4-piston billet aluminum calipers and drilled, drag race-style rotors. Those plate rotors are of course a great thing on a race car, but we were looking for something a little more suitable to the track and the street. So what we needed was a new set of brakes designed for such duty and a set of spindles to accompany them. For that, we called upon TRZ Motorsports and Aerospace, both companies that have helped us tremendously on Grandma throughout her golden years. Once we’re finished with the suspension changes, we’ll also be sticking a new set of Weld Racing wheels and shoes (no, not the prescription kind) on the old girl from Mickey Thompson and M&H.

TRZ’s Drop Spindles And Steering Arms

Shown here is TRZ's 1.5-inch drop spindles with the billet steering arms. The use of these components drops roughly 7.5-pounds over stock.

Our update begins with a set of TRZ Motorsports’ 1.5-inch Drop Spindles that are designed for use with early model GM vehicles with Camaro-type brakes. These direct replacement, TIG welded, chomoly spindles are designed for drag racing and Pro Street applications and effectively maintain optimum geometry when lowering the ride height for drag racing applications. In order to use these spindles, you must switch to a first-gen Camaro style braking system.

Each spindle drops roughly 7.5 lbs. from the stock part, so right away you’re looking at a loss of 15 pounds just in the spindles.

We haven’t made any changes to the overall geometry, but in addition to the 1.5-inch drop, it puts the rod end straight in line with the ball joint, so that helps with bump steer. – Todd Braasch

Also part of the package from TRZ — and actually required for use with the 1.5-inch drop spindles — is a set of billet aluminum steering arms, designed for early Camaro spindle conversions. Combined with the drop spindles, you can shave off 13 lbs. of weight, all with the added benefit of exceptional bump steer adjustability.

Explained TRZ’s Todd Braasch, “We haven’t made any changes to the overall geometry, but in addition to the 1.5-inch drop, the way the steering arm is bolted on, it puts the rod end straight in line with the ball joint. So instead of it being angled like the factory spindle does, this design helps with bump steer. You want the rod end side of the rack to be in line with the ball joint in order to completely eliminate the bump steer.”

“The steering arms have the two holes in them where the closest hole to the spindle be used for street driving to gain 15-percent more steering radius than the outer holes, which are essentially a drag racing-only setup.”

Aerospace Brakes

Delivering the new road-going stopping power for Granny is a set of 4-piston, Pro Street drilled, slotted, and plated brakes (Part #AC-205VRDSP) from our friends at Aerospace Components.

Built as a race car by design, Grandma currently sports plate rotors, but today, we’ll be making the swap over to a set of slotted rotors.

Designed for use primarily on ’67-69 Camaros, these brakes feature billet aluminum 4-piston vented rotor calipers, billet aluminum hubs, Hawk Performance pads, and drilled, slotted and nickel-plated rotors measuring 11-3/4 diameter by 13/16-inch thick vented rotors to keep cool under any driving conditions. These brakes are designed for use on vehicles that weigh under 4,000 lbs.

To outfit Grandma with an all-around set of brakes, we needed to trade out our drag race rotors with vented rotors, and that's exactly what we got with these 13/16-inch vented rotors that we're mating with Aerospace calipers and Hawk Performance pads.

From Buick Appolos and Skylarks to El Caminos, Olds 442’s, Pontiac LeMans, and more, these brakes will get the job done. “This was a kit that was originally designed to go on ’67-69 Camaros, Chevelles and other cars from that era that really used the same spindle,” explains Matt Moody of Aerospace. “We initially had a set for drag race use and then released a version for street use as it got more popular.”

The Pro Street version of the AC-205 brakes weigh in about six pounds heavier than their plate rotor drag race counterpart, and the only real differences lie in the accommodations for the wider rotor.

Said Moody, “The caliper on the street kit is wider to fit over the thicker vented rotor, but otherwise, the mounting hole locations are the same as far as the spread on the caliper, and the bracket is also different because of the larger diameter of the street rotor.”

The drag race kit measured 10-1/4-inches versus 11-3/4 on the Pro Street piece.

Installation

The TRZ spindles with the Aerospace-supplied caliper mount attached.

The hub, rotor/hub adapter, and the rotor complete the basic hub and brake assembly before being installed onto the spindle. From there, we can install the calipers and complete the proess with the addition of the screw-on nose cap.

Installation of our new components is a pretty straight-forward process if you’ve ever assembled a brake kit or swapped out spindles and/or steering arm on your car.

The Aerospace brake setup includes all of the hardware and components you need to get going (or stopping, rather), including a hub adapter should you need it. The hub, rotor/hub adapter, rotor, and the screw-on nose cap all complete the brake assembly. The supplied caliper mount bolts to our spindle, followed by the addition of the steering arms. With both assemblies complete, we can go ahead and install the hub/rotor to the spindle and bolt up the calipers. Our entire spindle/brake assembly then bolts up to the upper and lower control arms. From here, we need only to bolt the new steering arms to the tie rod ends and dial in our bump steer settings to get everything squared away and get us on our merry way to Project Grandma’s new goal of True Street duty.

Here's our final product with the spindles and entire brake setup complete and our steering arms installed to the tie rod ends.

Weld RT-S Wheels Wrapped in Mickey Thompson and M&H Rubber

The Weld Racing RT-S wheels (15x12.5 in the rear and 17x4.5 up front) wrapped in M&H rubber on the front and M/T ET Street Radial's in the back for street duty.

With all of that work complete, we’re down to the easy part, which is mounting our new tires (M&H’s on the front and Mickey Thompson radials on the rear) to our sharp Weld racing RT-S wheels. Much for the same reason that we swapped out our prior brake and spindle setup for our move from a race-only car to a street car, we’ve gone with the RT-S wheels and M&H/M/T tire combo for getting Grandma back onto the street. The front combo consists of a set of 17 x 4.5″ RT-S wheels, while the rear 15×12-1/4″ RT-S wheels are rapped in a Mickey Thompson Street Radial P275/60R15’s.

Wheel specs:

Front:
Part#: 71LP-7045B17A
17 x 4.5″
Backspace: 1.7mm
Offset: -19mm

Rear:
Part# 71LP-512B65A
15 x 12.25″
Backspace: 6.5″

Both front and rear bolt circles measure 5 on 4-3/4″

After some rest, ol’ Grandma how has her herself a new set of new set of wheels, some new shoes, and improved geometry for her shrinking (ride) height.

Article Sources

About the author

Andrew Wolf

Andrew has been involved in motorsports from a very young age. Over the years, he has photographed several major auto racing events, sports, news journalism, portraiture, and everything in between. After working with the Power Automedia staff for some time on a freelance basis, Andrew joined the team in 2010.
Read My Articles

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