Homemade frame ties, tube dimensions?

[swinger340]

I'm getting some tube steel welded in place for frame ties, however i'm not sure on the size of tubing. I was thinking 2"x3" tube steel, but not sure on the thickness. Its going in a 70 340 Dart, 4 speed. When I'm done building the motor it should be well into the 400+ horse power range. Thanks.

[Mopardad]

I've always used 2x3 1/8 wall thickness. Where they are cut through the floor, make sure that they are welded solid to the floor.

[swinger340]

Could someone explain cutting through the floor? I never knew this was needed. Thanks

[Mopardad]

The tubing should be cut into the rear rails so that the bottom of the tubing is flush with the bottom of the rails. The tubing runs up against the torsion bar crossmember. The top of the tubing should be up against the top flange of the crossmember. In order for the tubing to be run in a straight line the floor needs to be cut out, most of the cutting would be in the rear floor area. This would be a strip about 2" wide. Where the tubing meets the front crossmember I've always first welded a 1/8" plate to the tubing aprox. 3"H. x 4"W & then welded this plate to the crossmember. When the frame ties are finished & completely welded as I described in my earlier post you can tell that the car has less flex just by jacking the car up.

[Plum Crazy Chris]

Check out the thread, "Sub Frame Connectors" by 70Chall383 a couple days ago. I attached some photos from Turbododge that detail the operation.

[Mopardad]

Looks like the way I have done it.