65 to 66 are very similar. the only changes i believe is the grill area (looks) and the side ornament.
the 64 had a smaller v8 (260) and had a generator not an alternator. also some orther minor stuff. 64 to 66 interior was the same (maybe some minor stuff i dont know)
67 to 68 the bodies changed. the rear valance got well pushed in. go to google and find a pic. the steering wheel changed and more engine options was availble.
64-66 similar cars
67-68 simialr cars(got a little bigger)
69-70 Similar cars(got even bigger)
71-73 similar cars(holy crap thats a hood)
74-78 (uhhh is that a pinto)
Factory discs, rack and pinion, light weight and a 302 that can be modified highly. I tend to think of it as more of a Mustang than the 71-73's, in many aspects.