any torque arm needs articulation. your 14 inch travel is still limited by the length of driveshaft slip into the trans. most movement is in the rear spring shackle or 3 link if you go that way. the spring shackle at the front of the torque bar takes up any movement that is also limited by driveshaft travel. i used a trailer spring shackle for spring movement. no need for any heim joints
you could make your own shackle with a little flat bar and tubing with these