Installing a Torque Box in a 1967-1970 Mustang

Years of driving and exposure to the elements can start to cause your 1967-1970 Mustang torque box to rust and deteriorate. This can make your Mustang's frame twist under the torque of your engine. Prevent this from happening by installing an aftermarket torque box or replacing your stock unit. A new 1967-1970 Mustang torque box prevents body flex under load and keeps your frame from being twisted.

Installing a torque box on your classic Mustang is a challenging job that requires welding. If you can't weld, you're better off leaving the installation to a shop you trust. It also requires you to remove a large section of the interior and is best done on shells or Mustangs undergoing a complete rebuild. If you meet all of these requirements, learn how to install a new torque box on a 1967-1970 Mustang below.

How to Install a Torque Box on a 1967-1970 Ford Mustang

In this installation guide, we're going to walk you through installing a torque box on your Classic Mustang. Regardless of what torque box you're installing in your 1967-1970 Mustang, the process is largely the same. Find the Mustang torque box that fits your build and go with that one.

If you're still having issues with chassis flex after installing a new 1967-1970 Mustang torque box, there are other ways to stiffen your chassis. Adding a set of Mustang subframe connectors or a Monte Carlo bar can go a long way.

Tools Needed

• Spot Weld Cutter
• Welder
• Drill
• 4 lb. Sledgehammer
• Center Punch
• Jack and Jack Stands

Step 1: Jack Up Car

Jack up all four corners of your 1967-1970 Mustang with your jack and jack stands. Place the jack stands under the rocker panels on your car.

Step 2: Drill Out Spot Welds

Make a small indentation on all of the spot welds on the torque box with a center punch. This will split the two-piece torque box.

Drill out each of the spot welds. Be careful not to drill through the second panel on the torque box. This makes installation of the torque box easier since you'll have alignment holes already there when putting the two pieces back together.

Step 3: Test Fit Lower Portion of Torque Box

Fit the lower portion of the torque box into place between the frame rail and the Mustang rocker panel. This is a tight fit and may require you to use a hammer or jack to get it into place properly.

Step 4: Drill Plug Weld Holes into Lower Portion

Prep the lower torque box piece by drilling plug weld holes in the area where it welds to the front of the rocker, the side of the rocker, and the underside of the Mustang frame rail.

Step 5: Weld Lower Portion into Place

Reinstall the lower portion of the torque box and weld it into place. Both the driver's side and passenger's side are installed in the same way.

Step 6: Test Fit Upper Portion of Torque Box

Fit the upper portion of the torque box into place on top of the frame rail. It should line up with the alignment holes you made earlier.

Step 7: Drill Plug Weld Holes into Upper Portion

Prep the upper portion of the torque box by drilling plug holes in the area where it will sit over the frame rail.

Step 8: Weld Upper Portion into Place

Reinstall the upper portion of the torque box and weld it into place. Use the holes you created in the previous step and the ones made when you split the two pieces of the torque box originally to line it up.

Congratulations, you're all done!

Stiffen Your Chassis With This Essential Mod

While not the easiest job, installing a torque box on your 1967-1970 Mustang is a surefire way to stiffen the chassis of your ride. Find the perfect torque box for your ride below from our selection and stop worrying about frame flex.