In prep for this years Reunion and later, Drag Week, I finally got around to doing something I should have done years ago, adding sub-frame connectors to my Mach 1. I had looked around at all the different types and finally settled on the Tin Man Fabrications connectors. There seems to be advantages and drawbacks to each type, but I felt these would look the most "factory" when completed. Personally, I would have preferred the type that requires cutting a slot through the floor pan and keeping the tubing exactly in-line with the factory rear frame rails, but I didn't want to totally destroy the floorpans, so these are what I settled on. I am happy with the results though.
Here's what they look like after I got them, prepped them and painted them to match the car.
The first thing I did was to raise the car on jack stands as high as I could get it. Then, knowing that my floor is perfectly flat, I carefully measured at each corner of the car, on the frame, and made sure that it was not twisted while in the air. I didn't want to weld it into a twist. Surprisingly, each corner matched the other side perfectly and I didn't have to adjust the height anywhere.
The Tin Man connectors actually slide into the front frame rails about 6". That requires cutting off the rear tab of the front frame rail. It's the only cutting that you have to do, but regardless, once they are welded at the back, they're pretty much permanent anyway. I took my cut-off wheel and chisel and opened up the back while leaving the top portion of the tab. Most guys cut that rear tab completely off, but that leaves a big gap at the top that has to be dealt with since the Tin Mans are 2"x2" and the factory frame rails are more like 2 1/4" x 2 1/2".
They have a 1/4" piece of stock welded to the sides of the front to make up that difference and make them a snug fit along the sides. There's a reason for that. They recommend that you drill 2 holes on each side at 2" and 4" so that you can plug weld the sides and add a lot of torsional strength.
Here's a picture after I got them in and fitted after doing some fine tuning with a die grinder.
And here's a couple pictures after drilling the side holes and dressing the area in prep for welding.
Then I re-fitted them and marked at the rear where the paint needed removed for welding. I had one issue where the rear floorpan plug and screw were keeping the connector from fitting flush with the floorpan. I ground off the tip of the screw and gently persuaded the holes stamped edges a little flatter with a hammer. That was good enough to get a flush fit.
Here's a few pictures of fitting and dressing the rear.
And some pictures of them after being welded and wiping stuff down. Now all I need to do is lightly touch up a couple of places on the welding and then touch up the paint.
By the way, if you're wondering how I dealt with the fuel line right above the plug holes, I found the easiest way to deal with it was to worry about it, think about how to protect them, and then totally forget about it while I was welding. That seemed to work out quite well.
I was a little concerned about how low they would hang and if they would be easily noticeable after the installation. When I mocked them up, I stood back a ways and took this picture. Unless you are about 30' away, you can't even see them. They do hang down a bit in the back, which I'm not real keen on, but they won't be all that noticeable unless you're crouching and looking at the bottom.
Overall, I'm pretty happy with them and was able to finish the job in one day, minus the paint touch-up. It would have gone alot quicker if I had a lift. Doing this kind of work on your back, welding overhead, just plain sucks. I'm spoiled with my lift at work, and I
really need to get one for my garage! I'm kind of anxious to see how they make the car feel, but while I've got it up in the air I'm going to finish making a front driveshaft loop, and I'm also considering adding a set of exhaust cut-outs. The cut-outs will have to wait until after the Reunion though. I've got too many other things to finish in the meantime, like getting my line-lock on and finishing the truck.
