I have made my own subframe connectors. These are slightly modified from the first ones I made for my first Mach 1, but essentially the same. I can say that the first ones I made performed flawlessly. The downside to the strength is that they are slightly obtrusive on the rear floor. If you put down dynamat on each side of the floor, and then cut the underlayment around it, then it isn't so bad. Especially considering that only smurfs can really fit back there anyway, and they can't reach the floor.
I have them nestled perfectly into the front sub frames and thuroughly welded. I only notched the floor pans where needed. I had to make patches for the front of the rear torque boxes anyway, so I cut slot in the steel tubing long enough to slip it around the bottom piece of the torque box all the way to the back of it. It's welded all along the floor of the rear torque box, inside and underneath, and also internally welded to the rear frame rail where it becomes part of the torque box.
Here's a pic of the modified seat pan sitting in place, but I still need to finish cleaning it up.
I also used the subframe connectors as the main attachment points for a new transmission crossmember for fitting a T-56 in there.
I'm just getting started on this project again, so it's all a bit ugly still.
On my original Mustang, I had thought it drove like any car should. It was my first car. Taught myself how to weld, and put all the money I could get, and then some, into tools and parts/materials. I put in new floor pans at the same time with my original Mustang as well. With only those changes, the car was noticeably stiffer, and with the change, it felt like the suspension was finally working properly instead of just letting the body flex. I agree with everyone that says subframe connectors is one of the best mods you can do.
Dan
