Moser M9 Extreme Torque Arm Package for the F-Body

Project All Air — our 4th generation F-Body Camaro, has been under the scalpel undergoing a series of internal organ transplants. It is well on its way to becoming a nine second wheels up drag car powered by a nasty 454 cubic inch World Products LS7 Warhawk. The naturally aspirated LS-powered 802 horsepower engine will be pumping enough power to get tire shredding torque to the rear wheels.

Our latest performance upgrade involves a rear end change, replacing the wimpy stock rear end with a beefy Fabricated Ford 9-inch that would make Sir Mix-A-Lot proud and Kim Kardashian cry. Seriously – there ain’t no junk in this trunk. We wanted to give the Camaro a monster rear end package that could easily handle the rest of the drive train upgrades and wouldn’t be spitting gears and axles all over the pavement.

Moser M9 Package

We are upgrading to the latest Moser M9 package, complete with Moser’s freshest release – the F-Body Torque Arm – and are capping it off with ChassisWorks shocks, a perfect match for the bind free Moser torque arm. This combination is guaranteed to leave a rubber signature on the asphalt, letting everyone know that we were there.

Moser Engineering’s Fabricated M9 rear end and Torque Arm Package.

Moser’s M9 performance fabricated housing and Torque Arm package are perfect for the enthusiast who wants a performance piece with some serious strength and durability.

We wanted a true “fire and forget” performance rear end that could be bolted in, required very little routine maintenance, and could handle as much horsepower as we could throw at it. It’s a buy once and virtually race forever upgrade that bolts directly into place and doesn’t require special tools or skills.

The Project All-Air F-Body Camaro in STOCK form! Not anymore!

Moser Engineering

Founded by the late Greg Moser in the early ‘80s, Moser Engineering has built a solid red, white and blue reputation among racers. Moser Marketing Director Jeff Anderson explains: “Moser uses only U.S. made steel, forged in U.S. plants using Moser designed dies and tooling.” You just feel the sense of devotion to the U.S. and patriotic pride when you talk to the people at Moser. Jeff went on to explain that the company’s founder, Greg Moser, used a team of engineers to develop the proprietary material that the company still uses today. The company is now carried on very capably by his son Rob Moser – who grew up practically helping spline axles!

Moser’s product line includes high strength aluminum thru-bolt third members.

Key Features of the Torque Arm

The M9 F-body torque arm assembly is new to the Moser arsenal, and we’ve gotten our hands on one. There’s no doubt that a higher horsepower GM F-body needs some help in the torque arm area. The stock stamped steel simply won’t hold up to pressure.

There are a lot of great options in the F-Body torque arm world, and Moser’s is one of the most serious — going “ALL-OUT” with a radical Pro-Mod style design.

Check out some of the features of the M9 Torque Arm:

  • Constructed with 1.25” o.d. 4130 chrome-moly and all TIG welded, the Moser torque arm is patterned after the same style setup used in the Pro Mod cars.
  • The torque arm features a unique sliding front mount that allows the torque arm to slide and move freely, eliminating any chance of binding.
  • The F-body Torque arm assembly utilizes existing mounting points, eliminating welding or additional fabrication.
  • The Moser Extreme Torque Arm kit came with a 1.75” X .095” wall tube crossmember assembly that bolts into the stock mounting support. The crossmember assembly provides the front mounting point for the torque arm. There’s no doubt that this Torque Arm kit will handle all the power that we can throw at it and still keep the wheels on the ground.

Moser’s new F-Body torque arm features a sliding front mount for bind free operation.

Key Tech Features of the M9 F-Body Housing

We chose to upgrade our rear end from the stock version, certain that with the V-6 that came with the car, the rear end ratio was probably a little too wussy for our needs. The differential had a 10-bolt cover on it, but there was no telling what gears lay underneath. It was pretty much a given that the stock had to go, so we weren’t even going to waste time pulling the cover off and counting gear teeth.

The following features that make the M9 Housing a perfect for our application:

  • The Moser M9 housing features a fully fabricated and triangulated center housing, constructed with 1/8″ thick laser cut steel.
  • Beefed up with internal gussets, bulkheads, and a super thick 3/8′ faceplate, the M9 housing is tuff ‘enuff for any racing application.
  • A factory installed back brace on the housing for big horsepower support.
  • Extremely strong axle tubes constructed of 1/4″ thick DOM tubing with the standard 3″ outside diameter for any bolt on clamps that you may want to install.
  • Several choices in housing ends including ours – the Ford ‘big bearing’ Torino-style housing ends, which have a deeper bore for the 45mm bearings.
  • Choice of center sections, from Nodular iron to an aluminum center section which saves 14lbs over a stock center section. The aluminum center section is constructed out of T-6 grade aluminum with billet caps and billet steel adjusters.
  • Moser’s thru-bolt design minimizes the ring gear deflection that has plagued aluminum case designs in the past.
  • Choice of Gear ratios from 3.50 to 6.50, depending on the pinion size and desired torque.

We added some upgraded options to the M9 bolt in package for some additional insurance, starting with the Moser 40 spline axles that were gun-drilled and star flanged. For a massive axle, the weight is kept reasonable by eliminating the excess steel without losing any of the strength or structural integrity.

We capped off our axle tube flanges with a 5/8″ drive stud kit instead of press in or screw in lug studs. Moser sells the applicable wheel studs and drive studs for any of their axle flanges, ranging from 1/2 ” to 5/8 “. Drive studs look impressive and can handle a lot of torque, so we thought that the slightly more costly drive studs were cheap insurance against a busted wheel stud.

The M9 housing is fabricated from a single piece of 1/8″ steel and is a work of art.


Once we got our hot little hands on the rear end package for project car, we wasted no time in ripping out the stock components. As soon as the car was on the lift, the emergency brake cable came off the rear brakes, the rear sway bar was dropped out, the tunnel brace was removed, and the driveshaft came out. Once our initial enthusiasm died down a little, we took a look at Moser’s instructions to make sure that we were on the right path. We were spot on!

Dropping the stock rear end.

Next came removing the flexible brake lines up to where they mount into the hard line. Always safety conscious, we caught the brake fluid in a catch container and capped off the hard lines. Our F-body had a four channel brake system, with the electrical connector for the sensors attached to the forward bulkhead above the stock rear end housing. We disconnected the electrical connector and left the harness hanging from the rear end.

Once the brake lines and electrical were out of the way we could focus on dropping the stock rear end out of the car. Using our under lift hydraulic support, we supported the rear end and removed the lower shock mounts and rear lower control arms. When the panhard bar was removed, we were ready to lower the GM rear end and install the beefy M9 in its place.

Bolting in the new crossmember mount.

The installation instructions called for the new crossmember to be installed first. We found it necessary to leave the crossmember a little loose to allow for aligning the torque arm heim joint at the front of the torque arm. No hardware is provided with the crossmember, so using the original hardware or buying new metric bolts is a must.

Installing the center section into the M9 Housing.

Now it was time to prep the M9 rear end housing for installation. Moser’s Jeff Anderson reminded us to “clean the housing and axles tubes (inside and out) for any machining debris or shipping debris” that could cause premature bearing failure. Wrapping a mop handle with a couple of shop rags was the easiest way to clean the inside of the axle tubes, and our shop vacuum and a whisk broom took care of the housing.

Once we had a clean housing, we moved on to installing the third member studs into the housing face. Remembering to use thread locker, we installed all of the studs into the faceplate and secured them on the inside of the housing with nylock jam nuts.

Using a bead of silicone sealant around the gasket, we mounted the third member gasket on the housing and applied another layer of sealant on the other side of the gasket. Then we lowered the aluminum third member into the housing and the supplied washers and nuts were tightened to 40 ft. lbs in a criss-cross sequence.

Tightening down the center section bolts in a criss-cross fashion.

Our axles came with sealed bearings pressed onto the axles that do not require inner axle seals, so we could move directly to installing the axles into the assembly.

Before we seated the bearings completely into the axle tubes, we installed the caliper mounting brackets from our Wilwood Dynalite Drag Race Brake kit, which will act as the bearing retainers. The Moser axles came with bearing retainers, but due to the way the Wilwood calipers mount, we needed to use the Wilwood bearing retainers.

Once the retainers were installed and torqued down, we moved on to installing the torque arm.

Installing the heavy duty axles.

Installing the torque arm onto the housing using 3/4″ bolts, nuts and washers was pretty straightforward. The torque value wasn’t supplied in the instructions, so we went with the American Society for Testing and Materials (ASTM) recommended minimum torque values for a plain 3/4″ bolt at 113 ft. lbs, then we installed the solid rod end into the front end of the torque arm. The rear end was ready to roll under the car and lift it into place.

Mounting the torque arm to the housing.

Before we started raising the M9 into the chassis, we went back to the instructions to see if we had missed anything. Even though real men don’t read instructions, it pays to keep a close eye on the manufacturer’s recommendations. We discovered that Moser recommends adding the gear lube prior to lifting the rear end into place. Our team unanimously voted to follow the instructions, so we added Royal Purple’s Max gear lube (SAE 75W90) to the fill level.

Filling our rear end with Royal Purple’s finest gear lube.

Now it was time to finally get the rear end bolted in. We lifted the assembly into place, placing the springs back in the spring pockets and on the perches, making sure to index the springs in the rubber insulators.

Next came the lower control arm and shock installation. Jeff Anderson explained to us that using “good quality shocks and adjustable lower control arms enhances Moser’s slightly lower riding M9 designed rear end, taking full advantage of the engine supplied torque.”

Our project car continued to get the royal treatment with a set of VariShock double adjustable bolt in rear shocks from Chris Alston’s Chassisworks. The team was pretty stoked to get a set of these shocks and the mood in the garage area was as if everyone’s favorite sports team had just won the Championship.

The VariShocks allowed us to dial in the bump and rebound valving independently. Because the VariShock Shocks are available in several different shock travel lengths, these adjustments allow for a wide range of chassis tuning options.

Finalizing the build with Chassisworks VariShocks put smiles on our crew’s faces.

With the M9 rear end package bolted in and the torque arm bolted to the crossmember mount, all that was left to do was install the Wilwood Dynalite Drag race brakes.

We’re waiting for the engine and transmission installation in order to measure for a new driveshaft. Once the driveshaft arrives we can focus on setting the pinion angle and setting the ride height!

Setup Tips from Exotic Performance Plus

To ensure that we took advantage of every aspect of this high performance package, we went to the guys at Exotic Performance Plus (EPP), who had some real experience with the M9 torque arm.

EPP specializes in Moser rear end installations and was the first to install the M9 bolt in package into an F-Body. Bob Beam’s 1999 Camaro, which was showcased at the 2007 SEMA show, was the prototype installation. Bob’s Camaro boasts a 1.29 sixty foot time on street tires. He claims that it will be even faster this year. We asked Bob about initial setup tricks and tips to help us get going:

Bob Beam’s Moser M9 F-Body Tips:

  • Order the Moser M9 assembly with adjustable lower control arm mounts. Use the lower hole to mount the control arms initially. They just seem to hook up harder with the arms bolted in the lower holes.
  • Order the M9 housing with the anti-roll bar brackets installed. No matter what anti-roll bar you are using, you will want the support of the factory-installed mounts when you put some real horsepower to it.
  • Get the Back Brace Installed! Nothing beats the extra support of a back brace with the fabricated housing. No matter how much horsepower you throw at this combination, there will be very little if any deflection.
  • When plumbing the brake lines, take the time to weld in brake line tabs. They are much nicer and more durable than using plastic zip ties to hold the brake lines in place.
  • With the adjustable lower control arms and/or the adjustable panhard bar, preload the right side a little bit. This will help you launch and get down the track in a straight line.
  • A good starting point for the pinion angle is -2 degrees. Of course it will vary with track condition but -2 degrees is a great starting point.
  • Set up your rear shocks in the mid range of firmness. It doesn’t matter if you are using single or dual adjustable shocks, the midrange seems to help plant the rear tires.
  • The front shocks seem to do well at 1-2 range on the up and 4-5 range coming down.
  • Finally, you’ll want to get adjustable lower control arms. The Moser M9 F-Body naturally sits about a half inch to the rear. If you are using a taller tire, you’ll need to move it forward by adjusting the control arms. The M9 likes to sit a little to the right side as well. Adjustable control arms make these adjustments simple and easy.


Our project All Air Camaro is set for some really serious torque to the pavement with the Moser M9 package for F-bodies. We’ve gotten the super secret setup tips from one of the most experienced F Body Camaro racers, Bob Beam, and we have a brake system from Wilwood that provides stealthy power to our braking. All that’s left now is to get our power train installed and head to the track.

Our rear end is in and awaiting a driveshaft and tires.

More Info! — If you’ve always wondered about the 9-Inch vs. 12-Bolt F-body debate, read this!

While it actually boils down to personal preference when choosing between the Ford 9-inch rear end and GM’s 12-bolt rear end, there are some differences that make one more desirable than the other, depending on the application. Check out a few of our notes! We are defintely fans of the 9-inch, but some choose the 12-bolt because it’s a OE GM rear end.

12 Bolt vs. 9-inch: The Highlights

  • The major difference is in the housing section. The 12-bolt rear end features a housing section that incorporates a carrier case and the pinion support, whereas the Ford 9-inch features a “drop out” center section that incorporates the carrier, gears and pinion support.
  • The 12-bolt rear end is decidedly more involved to work on, due to the shim adjustments between the inboard pinion bearing and the pinion gear. The bearing is pressed on the pinion, so it requires removal and reinstallation to shim the pinion. Backlash for the ring gear is also adjusted with shims. These elements make the 12-bolt more complicated to work on.
  • The 9” rear end is easier to work on because of the removable center section which houses the entire gearset. Although the 9-inch pinion is also adjusted with shims, it does not require pressing the bearing on and off.
  • Installing axles on the 9-inch is also an added advantage. A retainer on the axle flange, which is held on by four bolts, is all that needs to be removed to yank the axles. The 12-bolt rear end utilizes ‘c-clips’ inside the rear end to keep the axle in place.
  • With the 9-inch axle retainer system, the axle stays in the housing if it breaks. When an axle breaks on a 12-bolt rear end, the axle comes out of the rear end axle tubes and tears up whatever metal it makes contact with.

Article Sources

About the author

Tom Bobolts

Tom started working for Power Automedia in early 2008 at the young age of 20. Starting off as an intern spinning wrenches in the PowerTV garage, Tom cut his teeth helping us build the very project cars we feature. Since moving inside the office, most of his time is spent writing and shooting installs - but he still finds time to get out in the shop. Outside of work, Tom enjoys a variety of different motorsports from Street Bikes, Muscle Cars and just about anything that demands high amounts of horsepower.
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