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October 20, 2006

Sub-frame connectors

One of the things it seems virtually all Mopar people agree with is that there are many huge benefits to stiffening up our old Mopar muscle cars. One of the best ways to do this has proven to be attaching what are called sub-frame connectors, which tie in the front and rear frames of the car. This relieves stress from the sheet metal during hard launches and extreme handling situations. There are numerous brands of these available, ready-made to go into a wide assortment of cars. However, I found a number of people who had fabricated their own quite successfully. I decided to take that approach and save some money. The material I used was 2x2 square tubing with a 1/8"-thick wall. The plates that attach to the forward frame were 1/4" thick 2"x4 1/2". The gussets for the rear were 1/16" mild steel.

The first thing I did was weld the 4 1/2"-wide pads onto the front edge of each tube. The front subframe was cleaned with a wire wheel prior to welding, and the whole piece was fitted approximately in place in order to mark the angle at which the rear would have to be cut to meet the rear subframe.

I cut the rear of the tubes so that the bottom of the frame would be flush with the tube. This resulted in the tube being brought up exactly to the bottom of the rear floorpan. I did not want to cut into the floorpan, as I have seen some do on A- and E-body cars. This junction was completely welded off on both sides prior to being plated.

This is the finished view of the rear, with the plates welded over the top of the joint of frame and subframe connector, which was also welded. Each side of the subframe connector had one of these plates, and each plate was welded on all four sides.

Here are both bars in place, painted with etching primer, as seen from the passenger side.

Both bars viewed from the rear.

The only thing that prevented this from being a super-easy job was the fact that on the driver's side, the parking brake cable passed directly through the space where the subframe connector needed to be. After marking the location on the tubing where the cable would need to go through, I drilled large 3/4" holes on either side. Realizing that this could possibly weaken the subframe connector on that side, I chose to weld heavy washers on the outside of the hole on each side. I took a drill with a 5/16" bit at the same angle the cable would pass through the tubing and made a smooth, angled channel for the cable. I was very pleased with how well it turned out, and can't wait for the day when I can realize the benefit that these bars will provide.

Posted in 2004-present | RESTORATION | body | suspension, brakes, tires, and wheels


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