UMI Performance 78-88 GM G-Body Bolt-In Rear Shock Tower Brace - Red

Bolt-In Rear Shock Tower Brace for the 1978-1988 GM G-Body, Bright Red

This is the bright red version of UMI's rear brace, and on a car whose underside gets looked at it reads as clearly as the red sway bars and control arms in the same range. Mechanically it is the same jig built assembly: 1-1/4 inch USA tubing MIG welded to 3/16 inch CNC laser cut brackets, bolted to the factory rear shock mounting points with the supplied Grade 8 hardware.

Its job is to stop the two rear upper shock mounts working in isolation, sharing their loads through one structure and stiffening the back of the chassis in the process. It suits both a conventional spring and shock rear and a coilover conversion, and it bolts to the chassis rather than the axle, so the rear housing under the car makes no difference to whether it fits.

Key Features

• Bright red powder coat to match UMI's red G-Body chassis and suspension range.
• Jig built for a repeatable hole pattern from unit to unit.
• 1-1/4 inch USA tubing MIG welded to 3/16 inch CNC laser cut brackets.
• Shares the load between both rear upper shock mounts to stiffen the chassis.
• Chassis mounted, so it is unaffected by an aftermarket rear axle housing.
• Compatible with coilover conversions, including UMI's own 3048 and 3049 kits.
• Grade 8 hardware included, tightened to UMI's published figure of approximately 25 ft-lbs.
• Designed to clear all popular exhaust systems.

Fitment

UMI lists these eight vehicles on its 3055 page and attaches no fitment warning or exclusion to the part number, so the application is manufacturer-confirmed and unqualified by vehicle.

Two installation variables are documented rather than hidden. Depending on the frame and the shocks fitted, the shock holes or the frame may need opening to 3/8 inch with a drill bit, or the brace may be fastened with 5/16 inch bolts, and some cars need an exhaust hanger moved or modified. Those are changes to the car that UMI sanctions, not changes to the brace.

Because the brace picks up the chassis and the upper shock mounts rather than the axle, the rear housing under the car has no bearing on whether it fits.

UMI publishes year, make and model only for this part number, with no submodel, trim, engine or drivetrain breakdown, so the fitment tags on this listing stop at model rather than inventing a trim.

Specifications

What's Included

• One 3055 rear shock tower brace in red powder coat.
• Grade 8 mounting hardware, comprising the 3/8 inch fasteners, locking washers and nuts the installation sheet works with.

No piece counts are given here because UMI publishes none for this part number. Its front brace and its frame notch kit both carry itemised tables; this sheet does not, so the contents stop at what is documented.

Shocks, coilovers and coilover support plates are not part of this purchase. On a UMI 3048 or 3049 coilover car the support plate arrives with the coilover kit and the brace fastener passes through it.

About UMI Performance

UMI Performance builds chassis and suspension parts at 509 Hemlock Street in Philipsburg, Pennsylvania, from North American raw material supplied by leading USA steel suppliers, with machine-guided precision bent DOM tubing, precision laser cut components, Tiger Dry Lac powder coat and welds laid by skilled and robotic welders. UMI builds the 3055 brace in a jig in Philipsburg and offers it in the same red and black powder coats used across its G-Body chassis range so an underbody build can be colour matched.

Related Parts

• UMI 3053-R front reinforcement brace in matching red, the front half of the same chassis stiffening job

FAQ

Each rear shock feeds its loads into its own patch of frame. The brace joins the two upper mounts so those loads travel through one structure, which is how UMI describes it: sharing the load and stiffening the chassis. On the road the difference reads as a rear end that stays composed over broken surfaces and under power rather than as a stopwatch figure.

Usually not, but UMI does not pretend otherwise. The brace uses the factory rear shock mounting holes and the supplied Grade 8 hardware, and the sheet then notes that depending on your frame and shocks you may need a 3/8 inch drill bit to clearance the shock holes or the frame, or you may fasten it with 5/16 inch bolts. That is minor fitting work, not fabrication.

UMI designed the brace to clear all popular exhaust systems, which is precisely where shop-made rear braces tend to fail. The exception it documents is that some cars need an exhaust hanger relocated or modified. If the pipework over your axle is custom, check the route during the trial fit.

Yes. UMI states the brace suits coilover setups as well as conventional spring and shock rears, and the sheet spells out the routing for UMI's own 3048 and 3049 coilovers, where the fastener passes through the coilover kit's support plate along with the brace, chassis and shock.

UMI asks for a final tighten to approximately 25 ft-lbs on the 3/8 inch fasteners, and the word approximately is UMI's. Because those same fasteners retain the upper end of the rear shocks, check your shock manufacturer's upper mount instruction too before you call it done.

No. The brace slides into the opening between the fuel tank and floor pan and the chassis, which is why the first positioning step is lining the slotted holes up with the driver's side of the frame. The step that actually matters for safety is supporting the axle before the shock bolts come out.

Not for this part. It bolts to the frame and the upper shock mounts, so the housing under the car is irrelevant to it. That is a real distinction from UMI's axle mounted rear sway bars, which are built around factory housings.

Grade 8 hardware is included, and the procedure works with supplied 3/8 inch fasteners, locking washers and 3/8 inch nuts. UMI does not itemise quantities for this part number the way it does for its front brace, so no counts are claimed here. Lay the bag out against the four shock mounting points before you start.

It is the same powder coat process in a different colour, over the same tube and bracket assembly with the same hardware and the same tightening figure. Red is the choice for a car where the underside is part of the presentation; the black version is identical mechanically.

They are the two halves of one chassis stiffening job, they share the identical eight vehicle G-Body application, and UMI made a single video covering both. Neither depends on the other, so fitting one first is fine, but the car feels more of a piece with the pair in place.

Drilling the car's shock holes or frame to 3/8 inch and moving an exhaust hanger are sanctioned in UMI's own instructions. Cutting, re-drilling or re-coating the brace is a different matter, because UMI's warranty excludes any product that has been altered, adjusted or tampered with. Modify the car where the sheet allows it, not the part.

No. It lives under the car in the space between the fuel tank and floor pan and the chassis, so the boot floor, spare wheel well and rear seat are untouched. UMI publishes no dimensioned drawing, so on a car with a fuel cell, a fabricated floor or a relocated tank, measure the space first.

UMI publishes a two year warranty from the original date of purchase against defects in materials and workmanship, to the original purchaser only, and it is not transferable. The same policy excludes misuse, use beyond the design limits of the part, improper installation, acts of God, shipping damage, any product that has been altered, adjusted or tampered with, components not made by UMI, incidental costs such as towing and labour, and normal wear items including bearings and bushings. UMI also states it cannot guarantee compatibility with other manufacturers' components. The printed sheet in the box still carries an older disclaimer that predates the current two year term, and the live policy page is the document that governs. Neither is a Black Ops Auto Works warranty.

Installation Instructions

1. Chock the front wheels, raise the rear of the car to a comfortable height and set stands securely on the chassis or the rear axle.
2. If the car is held by the chassis, put a jack or stand under the rear axle before going any further.
3. Slacken all four bolts holding the shocks to the frame, remembering that an unsupported axle will drop once they are out.
4. Take out those four shock bolts.
5. Feed the brace into the gap between the fuel tank and floor pan and the chassis, lining its slotted holes up with the driver's side of the frame.
6. Align the brace with the chassis holes and with the holes in the T-bar shock mount.
7. Drop the supplied 3/8 inch fasteners through the brace, then the chassis, then the shock, working from the top. On a UMI 3048 or 3049 coilover car the fastener also passes through that kit's support plate, so read the coilover instructions alongside these.
8. Fit a locking washer and a 3/8 inch nut underneath the shock T-bar mount.
9. Final tighten to approximately 25 ft-lbs.

Approximately 25 ft-lbs is UMI's own figure, qualifier and all, and it is reproduced rather than rounded into a hard specification.

The same fasteners hold the upper end of the rear shocks, so check what your shock manufacturer specifies for its upper mount before treating the job as finished.

Opening the shock holes or the frame to 3/8 inch, substituting 5/16 inch bolts, or relocating an exhaust hanger are all steps UMI allows for depending on the car.