Shelby used 'Traction Masters' on GT350s, but they were mounted above the axle tubes. The front mounts were also different, if I remember right. They didn't show from the side or rear. (They work quite well---I used them on both my '64 Custom/427 and my '65 Mustang GT/271-289.) The Custom would swap lanes from the violence of a 1-2 power-shift causing rear spring wrap-up. And the rear springs were 'Heavy-Duty' as part of the mandatory suspension/brake upgrade when ordering the 427.
KS