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Torque-arm Ordering Questions

Before you order a Torque-arm...
  • Torque-arm installation is straightforward and not difficult, but there are questions to address.
  • Whether you order by phone or on this website, these same questions must be answered when ordering a Torque-arm.
  • Information to help you answer these questions is immediately below.
  • You can read straight through, or use the questions as links to jump down the page.
  • Click on the FAQ button below for more information about MM Torque-Arms.

Tech Info

Questions you must answer before ordering a Torque-arm: Is the Standard Torque-arm suitable for your Mustang, or do you need the Heavy-duty version?
Two Torque-arm versions are available. To determine which Torque-arm is best suited for your application:
  1. Find your transmission's first gear ratio (or your transmission model) in the heading of one of the three Torque-arm Rating Tables below. The first gear ratio determines which table applies to your Mustang.
  2. Find your car's rear gear ratio in the far left column of that table.
  3. On the row with your rear gear ratio, look to the right. The next two columns have the rear wheel torque ratings for each Torque-arm. The first is the maximum rear wheel torque rating for the Standard-Duty Torque-arm. The second is the maximum rear wheel torque rating for the Heavy-Duty Torque-arm. These torque ratings refer to the peak rear wheel torque as measured on a Dynojet chassis dyno.
  4. Select the Torque-arm that has a rear wheel torque rating that is higher than the peak rear wheel torque that your Mustang produces, as measured on a Dynojet chassis dyno.
  5. Note: Take into consideration any future power increases you may make to your Mustang.


First Gear Ratio

Transmission Model
OEM T5, T45, TR-3650, TR-3550
TR-500, TR-600
Rear Gear Ratio Standard TA Heavy Duty TA
Max. Dynojet Torque
RWT (lb-ft)
Max. Dynojet Torque
RWT (lb-ft)
4.56:1 250 390
4.30:1 275 425
4.10:1 290 450
3.73:1 330 510
3.55:1 350 545
3.27:1 390 600
3.08:1 425 650
2.73:1 484 738

First Gear Ratio

Transmission Model
Close Ratio T5, TR-500, TR-600
aftermarket T-56, 4R70W
Rear Gear Ratio Standard TA Heavy Duty TA
Max. Dynojet Torque
RWT (lb-ft)
Max. Dynojet Torque
RWT (lb-ft)
4.56:1 289 450
4.30:1 318 491
4.10:1 335 520
3.73:1 381 589
3.55:1 404 629
3.27:1 450 693
3.08:1 491 751
2.73:1 559 852

First Gear Ratio

Transmission Model
C4, C5, C6, AOD, AODE
Rear Gear Ratio Standard TA Heavy Duty TA
Max. Dynojet Torque
RWT (lb-ft)
Max. Dynojet Torque
RWT (lb-ft)
4.56:1 349 544
4.30:1 384 593
4.10:1 405 628
3.73:1 460 712
3.55:1 488 760
3.27:1 544 837
3.08:1 593 907
2.73:1 675 1030
Does your Mustang have rectangular subframe connectors or round tube connectors?
  • Subframe connectors are required for a Torque-arm installation.
  • If you do not already have subframe connectors, your Mustang needs MM Full-length subframe connectors.
  • If you do not recall what type of subframe connector is on your Mustang, look underneath it. While you are there, measure the connector tube dimensions; you will need that information for the next question.
Are your existing subframe connectors strong enough?
Your Mustang must have suitable subframe connectors welded in place before installing a Torque-arm because the subframe connectors provide the attachment point for the torque-arm's front crossmember.

Your subframe connectors must not be smaller than the listed height and width dimensions. Larger tubes are okay! MM Full-length subframe connectors exceed the minimum required dimensions listed below.

Subframe Connectors - Minimum Required Dimensions
Shape: height X width Tube wall thickness minimum:
Rectangular: 1" X 2" .120" wall
Rectangular: 1-1/4" X 2" .083" wall
Rectangular: 1-1/2" X 1-1/2" .083" wall
Round: 1-1/2" diameter .120" wall

Do you have a suitable Panhard Bar?
  • A Panhard Bar (or a Watts Link) is required with a Torque-arm, and must be in place before the Torque-arm installation can begin.
  • The entire Panhard bar assembly (chassis mount, axle mount, and rod), as well as the method of attachment to the chassis, must be of sufficient strength to handle all lateral loads encountered while cornering.
  • If you do not already have a Panhard Bar, the MM Panhard Bar compliments the design of the MM Torque-arm, to provide the best performance for your Mustang. If you have another brand of lateral locating device, please contact us to ensure it is of sufficient strength for use with a Torque-arm.
Do you have suitable rear lower control arms?
  • To get the best performance from a Torque-arm suspension, suitable rear lower control arms are required.
  • Why? Because all of the acceleration forces that move your Mustang down the road pass through the lower control arms.
  • If the control arms do not have proper high performance bushings, the suspension may bind up, negating much of the advantage provided by a Torque-arm suspension.
  • MM has a variety of rear lower control arms that work well with a Torque-arm.
What rear spring rates should you have?
  • The MM Torque-arm provides a significant increase in rear traction; so much so that the grip at the front of the car will become the limiting factor during cornering, causing the car's handling balance to shift towards an increase in understeer.
  • To counteract the tendency to understeer, the rear spring rate should be raised to increase the rear roll resistance. This will shift some of the cornering load from the front tires to the rear tires, for the best performance.
  • Proper spring rates will provide both improved handling and better ride quality. MM has custom manufactured stock-location rear springs for Torque-arm suspensions, as well as rear coil-over springs in a variety of rates.
  • For help choosing new rear springs, please contact us.
Will your exhaust require modifications?
Standard Torque-arm
  • The MM Standard Torque-arm was designed to fit with a stock exhaust H-pipe. Some Mustangs may encounter slight interference because of the wide range of production tolerances for exhaust systems.
  • Aftermarket H-pipes and X-pipes have more variations, so there is a greater possibility of interference that must be dealt with.
  • The most common modification required done is to provide clearance for the Torque-arm Crossmember. It is not uncommon to slightly grind on the exhaust flanges for additional clearance, especially with aftermarket exhaust systems.
  • Some aftermarket H-pipes position the crossover tube closer to the rear of the car than others. There may be interference problems if the crossover tube is located closer than 2.25" to the front of the H-pipe connection flange. If your Mustang has one of these H-pipes, the crossover tube must be moved forward to provide clearance for the Torque-arm Crossmember. It is best to have this modification performed by a competent muffler shop before attempting installation of the Torque-arm. See the MM Standard-Duty Torque-arm instructions for details.
  • The three-piece Bassani X-pipes (manufactured since 2002) require proper adjustment, but no modifications. The one-piece Bassani X-pipes (those manufactured prior to 2002) for 1979-93 Mustangs will fit the MM Torque-arm after some modifications to the X-pipe. One-piece Bassani X-pipes for the 1994-04 Mustangs will fit with very minor modifications. The MM Torque-arms come with illustrated instructions on how to modify the earlier one-piece Bassani X-pipes.
Heavy-duty Torque-arm
  • The MM Heavy-duty Torque-arm requires a simple exhaust modification because of the size of the crossmember.
  • The flanges at the connection between the H-pipe and the tubes ahead of the mufflers must be moved rearwards several inches. See the MM Heavy-Duty Torque-arm installation instructions for details.
  • Any competent muffler shop can do this in under an hour.
Are you road racing?
If so, you may want our Racing Crossmember.
  • The Racing Crossmember is for racers who frequently remove their exhaust systems. If you remove your exhaust as frequently as only once per year, the improved access to the H-Pipe's exhaust flanges is well worth the additional effort during the initial installation of the Torque-arm.
  • The Racing Crossmember requires moving the exhaust flanges rearwards several inches, exactly the same as with the Heavy-duty Torque-arm crossmember. See the instructions for details.
  • Even though the Racing Crossmember is slightly more rigid than the Standard Crossmember, it is still only for use with the MM Standard Torque-arm.
  • To get the racing Crossmember along with a Standard Torque-arm, order MMTA-5.

Would a complete Torque-arm suspension package be more suitable?
Many people move towards gathering all of the parts associated with installing a Torque-arm in steps, installing the Panhard Bar and Rear Lower Control Arms separately. Others choose to get everything at once, in one of our money-saving Torque-arm Suspension System packages. If you choose to purchase parts individually, you can still get a money-saving package by starting with a Rear Grip Box that includes MM Rear Lower Control Arms and an MM Panhard Bar.