Well first, there was no SS in 1977 or 1978.
As for 1975 and 1976, the only exterior difference was the grille. 1975 used a black standard grille while the 1976 used a unique diamond-pattern grille. Otherwise the exterior was the same:
- Lower body dual stripes (one narrow and one wide stripe, only narrow stripe goes over wheel openings) - available in 5 colors: silver, red, gold, black and white
- "Nova SS" decals on front fenders and rear end panel (delete "Nova" or "Nova Custom" from front fender side)
- Black paint treatment on side window frame moldings and "B" pilar louvers (painting of underside of roof drip molding and belt line below windows deleted)
- "Nova SS" nameplate in center of grille (delete bow-tie emblem)
- Black finished headlamp bezels with bright perimeter molding
- Bright roof drip moldings
- Black painted sport mirrors
- 4-spoke sport steering wheel with "SS" emblem on shroud
Note: bucket seats and floor console were optional. Most Super Sports did have both but they were not standard equipment on the SS.
- F40 Heavy duty suspension (F41 Sport suspension optional)
- Rally wheels 14x6 (argent) with specific center hub and added P06 trim ring (14x7 Rally wheels when F41 Sport suspension or radial tires ordered)
Check out Don Coffman's website about his 1976 SS restoration for more pics: