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Baby's Got Back

Mark Williams Builds an 8-Second-Capable 8.8 Rearend

 

By Henry De Los Santos
Race Pages, August 2000

 
There are few things more exciting than the adrenaline rush of inching into the staging beams, matting the throttle against the two-step and waiting for the ambers to flash, in anticipation of rocketing your Mustang off the line to a 60-foot time that would make a Pro 5.0 racer jealous. Of course, there are few things worse than doing that, only to hear a loud bang as your rearend disintegrates and litters the track with broken parts and enough 90-weight to require a three-hour cleanup effort. Not only do you have to endure the wrath of the track officials and the racers who now have to sit and wait for your mess to be cleaned up, but you also have to tow the carcass home and build a new rearend for the car.

Knowing that our own project Terror2 will be an angry ape putting over 1000 horsepower to a state-of-the-art suspension system, we wanted to make sure this little monkey wouldn't be afraid of a little punishment. That kind of power and hook will make lesser rearends crumble like cookies in the hands of a two-year old, and since we wanted nothing but the best for Terror2, we went with one of the most reputable names in the industry when it came time to build a rear for our baby. Mark Williams Enterprises, Inc., was kind enough to step in with one of its latest Ford 8.8 packages. Mark Williams is known for high-quality driveline components, and has a list of customers that include everyone from street drivers to racers in NHRA Pro Stock, IHRA Pro Mod, and NMRA Pro 5.0. MW has any high performance part you need for a rearend, from spools, custom driveshafts, axles, modular aluminum housings, and complete thirdmembers, to Pro Street modular housing. And yes, our personal favorite, a complete 8.8 build-up package. For the Terror2, we ordered a set of 35-spline axles, a light-weight steel spool, bearings, and 9-inch rear housing ends.

NHRA rules state that in an application like ours, C-clip axles are a definite no-no. When a C-clip-style axle breaks, there's nothing to hold it in the rearend and it goes for a ride. At the least, it bangs up your car's quarter panels and drops the car on the ground. At the worst, it breaks at the top-end of the track at 150 mph, at which point you're going on a ride that you really don't want to be on. There are C-clip eliminator kits on the market, but there are considered by some as a quick-fix, since they tend to leak and they utilize a smaller bearing. A better, though more complicated fix, is to weld the bearing ends from a 9-inch housing onto the 8.8 housing. This allows the use of the big 9-inch bearing, which is pressed onto the axle and retains the axle at the outer end. Should the axle break along its length, the bearing and retainer hold the wheel end of the axle to the housing.
Speaking of the axles, there are a couple ways to go. Stock 8.8 axles have 28 splines where they meet the differential side gears. A common upgrade is to replace them (and the side gears) with 31-spline axles, which are significantly stronger. Quality 31-spline axles are good for somewhere around 700 to 800 horsepower in a good-hooking car. Obviously, the Terror2's blown small block will be well over that power level, so we decided to go with a he-man set of 35-spline axles. The next setup up the evolutionary axle food chain are 40-spline axles, but you're talking Pro 5.0-level power to require those. The Mark Williams 35-spline axles we used are forged from a nickel-chromium-molybdenum alloy, and will be able to take whatever power we can throw at them.

Likewise, in a single-purpose drag car like the Terror2, there's no need for a weak differential, so we opted to put the ring gear onto an aluminum spool. The spool is stronger and assures even transfer of power to both wheels, and the aluminum construction of the Mark Williams spool lessens rotational weight and overall mass. The gear ratio deemed optimum for the Terror2 is 3.73:1 but that may change after some experimenting at the track.
Once again, the guy responsible for doing the quality work on our 8.8 was Robert Varoujanian of Fast Track Performance. Robert got so into his work, and realized that he may want to build more rearends like this one, that he bought the jig from Mark Williams to properly weld the 9-inch housing ends onto the 8.8 rear. So, if you're planning on doing the same thing to your Mustang's 8.8, give Robert a call, because he can do the whole deal in-house.
What's next for the Terror2? Well, next month we'll address the rear brakes, and after that it goes on a trailer and behind James Lawrence's brand new Ford F-150 Super Crew pickup on its way to Texas. That's where David Wolfe will be welding in the rollcage and finishing the chassis work. With guys like Mark Williams, Robert V. and David Wolfe behind this project, does anybody doubt that this car will haul?