Steve Baur
Former Editor, Modified Mustangs & Fords
January 29, 2007
Photos By: courtesy of Crazy Horse Racing, DTS Custom Service

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Mmfp_0504_01_z DTS_custom_service LaunchingMmfp_0504_02_z DTS_custom_service Old_rear
While the stock 28-spline axles survived a few 4,500-rpm clutch drops prior to the installation of our supercharged 331ci engine, we didn't want to drive all the way to the track with our 500-plus rear-wheel horsepower and rely on them to get us down the track and home.
Mmfp_0504_03_z DTS_custom_service Removing_the_brakes
The 2300K Cobra disc brake kit required DTS to make a few custom changes to our assembly, including new brackets and calipers for the spacers.
Mmfp_0504_04_z DTS_custom_service Removing_the_old_rear
Crazy Horse's Glenn Knell removed our 8.8 in no time flat. He installed a spare 8.8 housing that was lying around the shop so the car could be moved around and not take up much space.
Mmfp_0504_05_z DTS_custom_service Shipping
Shipping something this big using truck freight isn't easily done. We went to our local FedEx freight company and sent ours off on a skid that we got from Crazy Horse Racing. A large pallet might do, otherwise you may have to build your own skid. Your local UPS depot may offer a truck service as well.

Horsepower is a wonderful thing. It's the driving force that plants us in the seat and puts the smiles on our faces. These days, it's extremely easy to make gobs of pavement-buckling power, but the rest of the drivetrain may not be up to the task, especially with two or three times the stock power level passing through the crankshaft.

The 8.8's stock 28-spline axles are not what you want to depend on when your rig is making 400, 500, or 600 hp. With the right application of the clutch, even a stock engine can snap these axles like the toothpicks they are.

Our behind-the-scenes project car, a '90 Mustang GT that makes about 590 hp at the crank, has, until this point, gotten by with the stock rearend, even enduring aggressive drag radial and ET Street tire launches. Going down the track, we also realized the stock, 140,000-mile control arms were way overpowered and did not offer the rearend control we needed. As we fully plan to exploit the power provided by the supercharged, DSS-built 331, we called DTS Custom Service (a subsidiary of Drive Train Specialists) and asked about what we needed to put beneath our Pony.

"The majority of 8.8s, new or used, already have bent axle tubes," says Scott Marrison, general manager of DTS. "This has to do with the way the housing ends are installed at the factory, combined with the fact that the 8.8s are prone to axle twist." Thank the torque of the 5-liter for that.

We know plenty of racers, however, who for years have been using the 8.8 behind 1,200hp cars after they've been beefed up. And DTS knows a thing or two about making rearends survive at the track. It currently runs a car in the Edelbrock Pro Series Xtreme Street class (mid-eight-second e.t.'s are the norm), and has many customers who run in other equally fast and faster classes.

While our project car won't quite see that much power, its 590 ponies do require a capable rearend. One of the issues we encountered when using our own 8.8 was with the 2300K Cobra R disc brake kit that was installed on it. The kit employs SN-95-length axleshafts, which created a problem with the C-clip eliminator axles we wanted to use.

The axle-flange-to-housing-flange distance of 3.25 inches would not allow the pressed-on bearing to sit in the correct location. DTS modified a set of brake brackets from North Race Cars (Gladstone, Missouri) to work with its own billet 8.8 axle-tube ends to get that gap down to an acceptable 2.5 inches while maintaining the proper brake-caliper-bracket position. This allowed the use of a shorter/ stock-length axle.

The billet tube ends are similar to the Ford 9-inch design and retain the axle without the use of C-clips. These ends are welded on and utilize a tapered roller bearing. DTS uses the tapered roller bearings because the bearing presses into itself when cornering. This is beneficial to bearing longevity, and it also prevents leaks.

The assembly is set in a jig. The bar is then pushed through to set the axle-tube alignment.

Once the axle tubes have been straightened and welded, support trusses are welded/bolted on. These are optional and should be considered if clutch drops loom in your future, as they further prevent the axle tubes from twisting or flexing.

With the DTS billet ends installed, the housing is then painted before the differential is dropped in. For our application, DTS used an Eaton Posi unit, which has been modified to accept DTS' forged spider gears for use with 33-spline axles. Mark Williams built the 33-spline axles that employ pressed-on wheel bearings to be used with the billet ends.

The Pro 5.0 3.55:1 ring-and-pinion set had been in our 8.8 only a few months, so we opted to reuse it. We also had DTS install a TA Performance main support cover, which it can offer to you as well.

Once the axle tubes are straight as an arrow and welded, DTS adds its billet ends and trusses.

To constrain our new axle, we contacted UPR Products for a set of new control arms. After mentioning our car's horsepower level, UPR sales associate and racer extra-ordinaire Jeremy Martorella recommended the company's Pro Series arms, which use aluminum and spherical rod-end bushings. He also sent us a set of UPR's urethane-bushed chrome-moly control arms, should the Pro Series pieces become too noisy for our street machine.

In addition, we ordered a set of UPR's Max-Cross subframe connectors, as our Pony was long overdue for a set, especially since we don't intend to put a rollbar in the car just yet.

Not all 8.8s are created equal, and if you're as horsepower hungry as we are, consider getting a quality-built piece such as the one we received from DTS. It's the only way you'll be sure to get all the enjoyment your high-horsepower Mustang can provide. Check out the captions to see what's involved in installing a high-performance back half for your blower.

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