by Richard Cordon III

Introduction
The very first step to lowering quarter mile times isn’t making more power, it’s constructing the chassis to correctly put the power to the ground. Once a "smart" vehicle platform is built, then the owner can confidently assemble a performance drivetrain. Really, what good is putting out loads of torque when that energy is absorbed by the chassis or lost due to wheel spin? Here at RatStang Restoration I’ve personally witnessed what torque can do to a weak Ford unibody. I’ve literally seen vehicles incrementally torn apart from excessive torque, and I’m not talking about Mustangs or Falcons that put out more than 500 ft lbs. In my shop, I have seen coupes, convertibles, and fastbacks affected from mild small blocks.

We know that early Mustangs and all unibody vehicles for that matter, suffer from body flex. Excessive body flex is the culprit that weakens a unibody over time. So how do you fix it? By reinforcing the body to lower the amount of flex the body has under heavy loads. One of the easiest ways to help lower flex in a unibody mustang is to install Subframe Connectors. They’re a fairly easy install and you can get them in both bolt-in and weld-in varieties.

	Canadian Mustang's 1965-1973 Bolt-In Subframe Connectors (PN TCE3140) These "bolt-in" subframe connectors are easier to install than regular "weld-in" connectors. However, if you have the ability to weld, welding in the "bolt-in" subframe connector is a smart idea.

First Things First
In this article I will be welding in "bolt-in" subframe connectors. The reason why I personally choose to go this route is the ease of installation. Also, I’ve found the overall performance and quality of the bolt-in subframe connectors to be equivalent, if not better, than subframe connectors that are designed specifically to be welded-in.

As mentioned in a related FordMuscle article, subframe connectors can only be as stiff as the body parts they are connected to (Installing Floor Supports: 1965-1970 Mustang). Although not absolutely necessary, I suggest upgrading to 14 gauge floor supports on early mustangs before installing subframe connectors to help stiffen the body. Because of the way they are mounted, the primary disadvantage of using just a "bolt in" subframe connector (without welding) is that they allow the vehicle to have more flex compared to a weld- in subframe connector.

Using the method of welding in bolt-in subframe connectors, I get the best of both worlds.

Ease of installation of the bolt-in subframe connector
Strength associated with the weld-in subframe connector

Getting Started
As mentioned, I’ll be using Canadian Mustangs 65-73 Subframe Connectors (TCE3140). They can be purchased at several different Mustang part suppliers. This is a pretty fairly easy job that can be done with a few basic tools.

Although the subframe connectors are in theory supposed to bolt right in, they don’t typically fit perfectly and do require slight modifications to get them to fit correctly. This is do to manufacturing variables of the connectors and the vehicles. I have been impressed with the overall quality, sturdiness, design and price of the Canadian Mustang connectors. They are all around good subframe connectors for early mustangs and Cougars. Let's do it.

We will start by doing a basic fit check to see how much modification the out-of- the-box subframe connector is going to need on this particular project.		I placed the bolt through the subframe connector and into the front leaf spring mount. This secured the subframe connector in place in order to check fitment.
Here I used a rubber mallet to get the front of the subframe connector securely against the rear of the floor support. I checked for a tight fit all the way around and verified there were no gaps larger than an eighth of an inch.		If a subframe connector is too loose or too tight around the floor support, you may need to bore out the leaf spring bolt mounting hole on the subframe connector to get correct fitment. A drill or a die grinder to bore out the hole is OK.
After it was bored out, I repeated step 3 and checked for fit again. Once the fit was correct I tightened everything into place with 6-inch C-Clamps. Note: If the top of the subframe connector is closer than a 1/4-inch to the floor pan at the drain channel and near the rear torque box I recommend later welding it to the drain area to prevent friction between the two parts. See Photo		Next, I marked the floor where the subframe connector and floor pan contact each other.
In this shot, I mark the rear mount and all mating surfaces, then I removed the subframe connector from the vehicle.		I used a 3M strip disc on a die grinder to prepare the underside of the vehicle for the subframe connector.
Then I wiped down the whole surface with Lacquer thinner to remove any oil contaminants.		Next, I gave the whole surface a once over with a Scotch Brite abrasive pad.

(Installation continued)
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