The 67/68 Cougars/Mustangs was a different body style and more narrower than the 69/70 which is wider body style.
Usually the 69/70 mustangs and cougars share the same suspension mods. Except the cougars have always had the longer rear leaf springs than the mustangs. Something like 3-4" longer than the mustang rear leaf suspensions. But the front suspension is the same for the mustang and cougar (67/68) and (69/70).

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347 Stroker/XE284H(284/296 dur, 240/246 dur @ .050), BG 650 VS Speed Demon, Ported Victor Jr intake, Jack Roush World Product (ported from 180cc to 195cc) Jr Heads(upgraded to 2.02/1.60 valves) 260cfm/190cfm @ .550 lift, 11:1 comp... 450-475HP