With the new upper housing bushing and upper mount in place, the last step was to install the Pro Series upper arm. Once again, Jeremy adjusted the new arm to match the length of the stock arm, and torqued it to about 85 lb-ft. Featuring a heavy-duty 1-1/4-inch-thick turnbuckle, and a 7⁄8-inch Teflon-lined, chrome-moly Heim joint, the UPR arm not only provides easy pinion-angle adjustments, but it is obviously much stronger than the stock arm. Working in concert with the rugged mount and spherical upper bushing, it obviously eliminates any slop in the rear suspension. By the way, the length of the upper control arm is one of few differences between ’10 and ’11 Mustangs, so don’t try to install an upper arm meant for a pre-’11 ’Stang.