We Dig Deep into Strange Engineering’s Ultra Fab Rearend

For over 50 years, Strange Engineering has been on the forefront of chassis and suspension technology. We caught wind that the Morton Grove, Illinois-based company was coming out with fabricated 9-inch housings and knew it would be a stout piece. Once we heard they were building an Ultra Fab rearend for a racer with a GM A-body we jumped at the opportunity to follow along.

The rearend is being built for a dedicated drag race Chevelle. That means it has some lightweight components in it that might not be suitable for street use. This purpose-built piece is stout, and it all starts with the Ultra Fab housing, which fills a void in Strange’s line of 9-inch rearends.

With everything from basic street rearends to Top Fuel billet floater housings, the Ultra Fab line of 9-inch housings are perfect for street and race cars alike. The housing centers are constructed from 0.125-inch alloy steel with a heavy-duty 0.375-inch faceplate. The triangulated internal construction gives you loads of tube support, reducing axletube deflection when big power is transferred to the tires. This allows for more consistent and straighter launches. Internal gusseting braces the end of housing tube and increases the overall housing stiffness. Strange slots the tube insertion locations, which allows for complete welding of the tubes to the housing. The housing is designed to provide the clearance necessary for cases with heavy-duty main caps and also allows the use of 9-, 9 1/2-, and 10-inch gearsets. Our housing is built to GM A-body specs for the Chevelle. The suspension pickup points are in the stock location and the width is stock.

The internals are built for one purpose: going fast. The centersection starts with Strange’s Ultra HD aluminum case that is filled with an extensively lightened 4.11:1 ring-and-pinion. A simple lightweight spool ensures power is equally distributed to both rear tires. Power is transferred through a set of 40-spline, pocket-milled, scalloped, gun-drilled axles. The rearend is finished off with a set of Strange drag race brakes. These are lightweight and compact, yet have tons of stopping power when it’s needed.

The Ultra Fab 9-inch is an awesome piece for street and race cars alike, and the nearly limitless ways to fill it make it versatile enough for nearly any project.

01.Strange Engineering’s new Ultra Fab line of rearend housings gives racers and street performance enthusiasts alike a lightweight, super-strong option for 9-inch rearends. We followed along as Strange built a new Ultra Fab 9-inch for an A-body drag race customer.

02.The build started with Strange’s Ultra HD Aluminum 9-inch centersection. The centersection was ready to be filled with a host of lightweight race parts.

03. First, the lightened ring gear was bolted to the Strange spool. The spool is an extremely simple device that guarantees equal amounts of power are distributed to each rear tire at all times.

04.Low-friction bearings are then pressed onto both ends of the spool.

05. Next, a low-friction bearing and spacer are pressed onto the pinion gear. Strange used a low-friction bearing for this build due to the nature of its use.

06.Shims are placed behind the low-friction bearing on the pinion gear.

07. The pinion support and yoke are then installed.

08.Next, another low-friction bearing is installed in the pinion support in the centersection before the pinion assembly is installed in the centersection.

09.With the pinion installed, the technician checks the pinion depth.

10.If the pinion depth needs to be adjusted, the pinion assembly is removed and the shim pack is changed until the correct depth is achieved.

11. Next, the spool and ring gear are installed. This assembly is held in place with billet main caps that bolt through the case. With the assembly installed, backlash is checked and adjusted to the required amount.

12.A marking compound is applied to the ring gear and then the assembly is rotated. This allows the technician to see and examine the gear engagement. Adjustments can be made to change the engagement so the pattern is in the correct location on the gear face. This will ensure strength, reliability, and smooth, quiet operation.

13. The fabricated housing is stock width for an early GM A-body. It also has suspension pickup points in the stock locations. The lower control arm mounts have four mounting positions, allowing the end user to make instant center adjustments and control how aggressively power is applied to the tires.

14. After the centersection studs are installed in the housing and the gasket is put in place, the centersection is installed into the housing.

15.This build called for many lightweight parts, including axles. Strange used 40-spline gun-drilled axles with pocket-milled flanges for extra weight reduction. Thread-locking compound is applied to the 5/8-inch wheel studs prior to installation.

16.The rearend is completed with a set of Strange Engineering’s drag race rear brakes. These brakes feature solid, lightweight rotors; billet aluminum fixed four-piston calipers; and billet aluminum caliper mounting brackets. These mounting brackets have a dual purpose in that they retain the axles in the housing, too.

17.With the correct spacers in place, a set of low-friction bearings are pressed onto the axles.

18.The axles are then installed into the housing and secured to the mounting bracket with four bolts.

19.Lastly, the brake rotors and then the brake calipers are installed along with the brake pads. The calipers are a fixed design and require shimming. This ensures the calipers are perfectly centered over the rotors and the brake pads don’t grab one side before the other.

20. The finished Ultra Fab rearend is ready to make passes!