[MrPbody]

For the most part, they're the same, from '70 thru '72. The headlights and tail lights changed. The 2-door cars are on a 112" wheelbase, while the 4-doors are on a 115".
For body part interchange, contact your better local wrecking yard. They will have an interchange manual, that will tell you which fenders, hoods, etc. will fit.
Malibu (2-door) and SS (no 4-doors) were both options on "Chevelle". Aside from running gear and certain interior appointments, the only difference is the badging.