I have a solid 65 fastback and want to stiffen the frame. I have the TCP subframe connector with crossbar. I am planning to put in a 351, but preparing for it. Is the subframe connector enough or do I need to upgrade to 67 torque boxes. Can I do the boxes later? I read in one of the Mustang Monthly articles that someone did both. What are your thoughts?

 

Well, I would use the phrase "68 torque boxes" since the 67 cp/fb had them only on the LH side, but yes, adding torque boxes would be more important than subframe connectors.

 

Can you do torque boxes after subframe connectors? How much do torque boxes usually cost I am not a welder.

 

i wouldn't think more than 30-45 mins labor to weld each one in. especially if you do the fitting and prep the metal.

 

Any decent subframe connector would come all the way to the torque box. If it didn't. it would be useless anyway. Subframe connectors also should be welded, bolting them on would allow too much flex to be useful. If the connectors were already in place, likely they would need to be cut and modified for the torque boxes.

 

Fitting the torque boxes is quite a job. By just looking you would think, just slip them in there and weld them. Getting them in can be an SOB. All the boxes I have installed have not fit very good. I think they were American industries. Not sure if anyone else makes them.

 

torque boxes seem like a pain. I already have the subframe stuff and thought that would be good enough, but it sounds like the torque boxes really help. I would think the subframe stuff would help more?

 

I used the 67 convertible torque boxes on mine - both sides. I used TinMan subframe connectors, which weld inside the floor supports. Since the floor supports are so thin, I welded a piece of 1/8" flat steel down the outside of each to connect the subframe connector to the torque box. I also welded it to the floor and ran a piece of 1" angle steel over to the rocker panel. It is pretty stiff :-).

The torque boxes are a pain to get in there.

 

Dynacorn makes an excellent torque box, which comes epoxy primed and unassembled. Glazier Nolan uses and sells these. Since they come unassembled, they are a lot easier to install.

 

Torque boxes are so critical that every Mustang convertible made from 64-73 had them. In 1967, coupes and fastbacks got the left one, and from 1968 on, every single Mustang made had them. None, however, had subframe connectors. So, with Ford calculating every penny of cost to figure what the cars needed, which do you think is more important? I won't say don't do them, but torque boxes, export brace, and Monte Carlo bar will stiffen the car so much you'll feel it on a straight, level road.