I love the 77.
Last year of the flat rear window.
New style interior getting ready for 78.
And in a review the 77 was actually regarded to have quite good build quality :p
The HP went up actually.
165 in 75 (base), 180 in 76 & 77 (base)
L82 had 205hp (75) and 210hp (76 & 77), but still that's not really enough.
This is just my opinion but if you get one of these years, be prepared to either live with having a good cruiser that is, in the scheme of things, pretty slow, or get ready to put money into the engine. Either way, because they are hard to find with the 4 speed manual, I would always think about upgrading the 3 speed auto to a 700R 4 speed (what was in the C4)
A 77 is what I would have bought if I didn't get the C4 (no offense to anyone, but the C4 is a far better car, but with a hell of a lot less character)