Hello, not exactly sure what we're looking at, but that does not appear to be a Mustang II rack & pinion due to its dimensions. There are a lot of variation of Mustang II suspensions... many aftermarket companies have roughly copied the design. To help you identify what you have, a picture of the
control arms / shocks / cross-member would be more effective. You can also just google for pics of Mustang II front suspensions.
Generally what you'll have are upper &
lower control arms, with a captive spring between the lower control arm and the cross-member. A shock goes through the spring, the spindle holds the disc brakes and connects to the rack & pinion steering. Strut-rods are connected to the lower control-arm, or a gusset welded to the cross-member to add lateral stability. Stabilizer end-links are also connected to the lower control-arms.