The Ford 8.8-inch rearend has many things going for it when it comes to strength and popularity. When you combine its overall strength with the astronomical number of the 8.8-inch rearends produced for Ford passenger cars, trucks, and SUVs, you grasp the motivation by the performance aftermarket to develop it even further.
Historically, performance enthusiasts and racers embrace significant components like engines, transmissions, and rearends within a “sweet spot” of mass availability. Compared to the 9-inch Ford rear that had ceased OE production in approximately 1986, the 8.8-inch rearend has been placed in high production vehicles from 1985 until recent times, which means they are now in aged vehicles sitting in boneyards.
Two of the key performance manufacturers utilized for the 8.8 builds by the Horsepower Wars teams are Moser Engineering and BMR Suspension. We specifically followed the $10K Drag Shootout’s Team Out in Front’s “White Boy Rick” 1996 Mustang build. Both companies took an active role in offering expertise for the goal of their “bang per buck” race car.
“Surprisingly, the factory OEM 8.8 rearend is beginning to thin out when it comes to easy junkyard access,” Jeff Anderson, Marketing Director at Moser Engineering describes. “With the continued popularity of the 8.8, we decided to produce a new housing and improve some areas where the original 8.8 was lacking.”
So, with Moser’s engineering effort completed, they now offer an aftermarket 8.8 housing with a modular casting, increased webbing, and an enlarged axle tube diameter. “Though it is generally strong, the 8.8 had smaller axle tubes,” Anderson says. “The only way to get a performance three-inch tube in the center section is to bore the casting, which weakens it. Some use a small tube with a larger three-inch tube welded to the outside, but that gains no maximum strength to the overall rearend.”
Since the General Motors 12-bolt differentials of the 1960s, racers needed to retain axles with more strength than the small factory clips used inside the differential. The strongest method is based around an early Ford axle design that uses a press ring at the axles’ outer bearing. – Jeff Anderson, Moser Engineering
Since Team Out in Front’s ’96 Mustang was originally a V6 model, they found a junkyard housing from a comparable Mustang GT and braced it as best they could. This bolt-in replacement better accepts high-strength internals from Moser Engineering.
The 2020 $10K Drag Shootout season followed a “no-prep” competition layout, so the team was banking on less stress for the factory diameter axle tubes. This upgrade also offers an almost bolt-in suspension setup with the help of BMR Suspension components.
“The BMR Suspension control arms are available in several configurations including upper and lower sets with double adjustable chrome-moly rod ends, heavy-duty spherical rod ends, and those outfitted with poly-bushings,” describes Kyle Briese from BMR. “Our assortment of rear control arms also offer options with or without spring perches and with both single and double adjustable ends.”
Marcus Thompson and his team had the goal to get a Mustang to build for the competition. The team has extensive experience in getting the Fox-body platform to handle big horsepower, but with reasonable suspension modifications. Extra money was spent on double-adjustable coilover racing shocks from QA1 Precision Products to give the rear suspension the adjustability needed for the dragstrip.
Compared to the chrome-moly rod ends, the performance enthusiasts who drive on the streets may opt for the control arms with spherical bearing ends. These stainless steel bearings are engineered to handle the highest compression loads while also taking on day-to-day usage. If improved performance over stock control arms but with a quieter ride is your desire, the polyurethane bushing arms would be your choice.
Another crucial piece of BMR performance hardware for getting the most from the factory Mustang suspension design will be relocation brackets for the lower control arms.
“Our relocation brackets bolt directly over the original lower control arm mount on the housing,” notes BMR’s Frank Steadman. “These brackets have three mounting positions, which allow you to change the instant center point with your control arm geometry. When big power is put to the ground, changing this lower control arm angle can control wheel hop and provide better launch characteristics.”
The final piece used on “White Boy Rick” was a then-prototype anti-roll bar that BMR created exclusively for the $10k Drag Shootout, which bears striking resemblance to the production S197 anti-roll bar proven on 7-second street cars. This 1.375-inch DOM anti-roll bar kept the Mustang launching flat, even, and controlled on the no-prep surface using 28×10.5-inch Mickey Thompson slicks. In fact, it worked so well that BMR has since decided to put it into production.
The team welded Moser 8.8-inch Mustang non-C-clip housing ends onto the Mustang GT housing. These housing ends will accept the larger 35-spline Moser axles and a related spool. Jeff Anderson explains the elimination of the factory axle retaining clips with this combination of components.
“By not relying on the C-clips to retain the axle, you prevent the axle and wheel from exiting the vehicle,” Anderson describes. “Once you reach a certain performance level in any form of racing, the ruling organizations mandate the use of C-clip eliminators for obvious safety reasons.”
With suspension mods underway, others from the five-person team concentrated on finishing the internals of the differential. Each of the $10K Drag Shootout teams has that “one guy” savvy at this process, including the proper ring and pinion mesh adjustments.
What the teams were going for at this point was achieving the definition of proper gear backlash. This backlash is “the gap and spacing between the pinion gear tooth and the mating ring gear.” This gear mesh and tooth contact allow for a necessary film of lubricant between the meshed gears.
Team Out in Front chose a 3.55 ratio ring and pinion and used a Moser R88 setup kit supplying all the necessary components to perform a fresh ring and pinion gear installation. The kit includes differential and pinion bearings (including all related bearing cups and cones,) plus the pilot bearing, pinion support shims, adjustable pinion collar, pinion seal, pinion nut, gasket, gear marking compound, and ring gear bolts.
Following the straightforward assembly procedure for the 8.8 differential, the pinion is installed into the housing first with a pinion depth tool. You can use an OEM-style crush collar to set the pinion depth, or in the case of an assembly suited for the dragstrip, a solid spacer is installed and adjusted to depth with solid shims.
The ring gear and spool assembly are set into the housing with all Moser differential bearings, cups, and cones. With the bearing caps torqued into place, they added one more critical Moser component increasing the 8.8 strength exponentially, a Moser Performance gear cover. Not just any standard stamped metal cover intended to contain the gear lube, this is an engineered cover made from heavy 356-T6 machined aluminum.
“I always tell enthusiasts, regardless of horsepower, if you are going to lean on the loud pedal quite often, a performance cover is going to help in a bunch of different ways,” points out Anderson. “Ultimately, you are trying to stop any flex to your ring and pinion mesh as you apply power. That is a very common source of rearend failure.”
Anderson finishes, “Essentially, your ring gear wants to push back against your differential bearing caps with a tremendous force. The strong cover combined with the heavy set screws prevent those caps from flexing.”
Wrapping It Up
Even with quite different components that BMR and Moser each offer for the Ford 8.8 rearend, it’s obvious that both companies believe it’s here to stay as a performance cornerstone. Whether it be modifications that keep this rearend design well ahead of the horsepower thrown at it or suspension pieces that transfer that power to the ground, the team Out in Front Mustang illustrates these positive attributes.
Sit down and enjoy the $10K Drag Shootout 3 on HorsepowerWars.com and see how these four teams implement the Ford 8.8 rear into their individual entries. When it comes to the final race day episodes, the 8.8 handled all the power that their various turbocharged powerplants could throw at them.