Working factory cruise still on my '74 as well (it was a Brougham originally). But cute story... when I first picked her up from western NY 5 years ago and drove her home to MA, I couldn't get the cruise to work on the ride home. Didn't think much of it, old as she was. Last year before our big drive to Mississippi though I was thinking it'd be nice to get that working again for that trip! So I mentioned it to my mech (sadly I ain't a motorhead, I don't do much of my own work) and he said he'd take a look. After getting off the phone with him it occurred to me, you know, I had never so much as TRIED it again after that first day! So on a lark I tried it on the way home from work that night... worked like a charm of course!! So called my guy back and sheepishly said, "Uh, never mind..."
Still not sure if there was a problem with it 5 years ago that cleared (I'd since had the carb rebuilt), or if I just triggered it wrong for some reason on that first drive home, not being familiar with it yet. In any event, turns out I may have had a working cruise control for five years I just never knew about!