Those look great I was planning on making some this spring for my 71' dart. I was thinking of using .125 thick tubing is the .085 thick enough? Can you lift the car with a jack under the new frame tie without it bending?
.085 is 1/8 inch, and I don't think I would try to jack the car up using the center of the connector but towards one end or the other I wouldn,t hesitate at all.
They are right up against the floor pan pretty solid in a few places, but still.
Jacking it up in the center might bow them a little.
Especially if using square/rectangle tubing, I would use .125" wall. .083" is going to give more, and as mentioned, running over a speed bump or jacking up the car is going to give you issues as well.
I run my suspension kinda high anyway, so speedbumps are not even close to being an issue. (about 9 inches of clearance) plus they are hardly any lower than the original subframe sections (1/4 in lower in the front and about 1/2 in lower in the back.
I noticed that the left front fender does not try to lift as much from engine torque after they went in.
