Casey, I’ll bet all convertibles came with two boxes. The torque boxes would be a good substitute for the missing roof.
Here is the actual text of the question and answer:
I have purchased a 1967 Mustang fastback with a factory 6-cylinder engine. My plan is to convert it to a V-8 car, changing the rear end, front suspension, transmission, and engine. After owning several V-8 Mustangs I know that they all had a torque box installed on both sides of the front subframe. But the 6-cylinder car I bought only had the torque box on the driver's side subframe rail. I have looked at several more 6-cylinder cars and they are all the same, with a single torque box on the driver's side subframe rail. The one on my car needs to be replaced along with the rusty floor. My question to you is should I install torque boxes on both sided of the subframe the way they were on factory V-8 cars? If I should do this please explain why.
Before I answer your specific questions permit me to say a few words about your project in general. In addition to changing the components you mention, namely the engine, transmission, front suspension, and rear end, you will also need to change the engine mounts, driveshaft, rear brakes, exhaust system, and rear wheels (from wheels with a 4-bold pattern to wheels with a 5-bolt configuration). The radiator should also be changed, as should the front wheels (again, from a 4-bold pattern to a 5-bolt pattern) And there is plenty of miscellaneous that you’ll need to change as well, such as the throttle linkage, transmission linkage, some wiring, and so on.
Given all of this, not to mention the time required, you’ve normally much better off buying a V-8 car to begin with. But, of course, if you just happen to already possess a lot of the needed parts, and consider the time you’ll invest as therapy rather than work, go for it!
The torque box was a rather innovative structural addition that significantly stiffened the Mustang’s partially unitized body construction. Because they weighed more and had more powerful engines Ford opted to install two on V-8 powered cars. Since you are converting your ’67 to an eight cylinder, and especially since you have to replace the original torque box and floor in your car anyhow, you should certainly install the V-8 Boxes.
