Does anyone know if there are any differences in components in the suspension between 69/70 Cougars and 69/70 Mustangs. I have a 70 XR7 Q code and it does have a rear swaybar but that is all I know. 
Front suspensions, are the same between the Mustang and Cougar.
Rear suspensions are different between the two. Leaf springs on a Cougar are longer, they also have different mounting hardware than a Mustang. Rear sway bars are different, so are the sway bar plates.
While the front suspension is the same between the mustang and the cougar of the same year, they are different from 69 to 70.
IIRC the spindles use different wheel bearings. There may be other differences.
Tie outer rods are larger in 70, as were the inner & outer bearings. The drag link is also different w/ larger holes for larger inner tie rods. Strut rods have different threaded ends. No smaller threads & no hole for cotter pins.
Scott - are you sure that the rear sway bar is different between 1970 Mustang and Cougar? I know the sway bar links are longer on the Cougar (and the Mustang uses a D0ZZ link kit), but I was under the impression that the 1/2 inch sway bar itself was the same. Please confirm. Thanks!
Mustang & Cougar rear bars are different.