New Member, New Duster

What makes you say the alternator and starter were in such bad shape? Ugly? Greasy? That don't count. Wait on those til they show signs of dying. Spend your money elsewhere at the moment.
Though I thought I saw somewhere above where you were replacing battery cables? If it cranks starts and runs at all those probably aren't the cause of your running issues at the moment either but after 40-some years I'm sure the insulation ain't very good anymore, and it's very likely the copper inside the insulation has turned a nasty green and is corroded. Which gives resistance and inability for electricity to flow like it should. So probably a good move. But whatever you do DON'T hodge podge those. Like using the universal replacement terminal ends with the 2 bolts that pinch the cable ends to itself. Electricity is no place for a rig job.
Find a buddy with a crimper and replace the lugs the right way and seal em with heat shrink.
But we're still getting far away from the problem at hand. Get it running, first and get the bugs out that are causing the issues AND THEN start replacing "ugly" parts and/or upgrading.
Otherwise you may unknowingly add to your frustrations. Don't be replacing parts that don't either get you to a good baseline (like tune up parts, vacuum lines, etc) or directly (and knowingly) solve the problem. Once it runs as it should there will be plenty of time to upgrade "ugly nasty" stuff for the sake of getting rid of "ugly and nasty".