78 caprice wagon killing alternators

i am really stuck... my 78 wagon started killing alternators. i had the starter go and that is when this all began. i got the car to start again but then the headlights got dim and it wasnt charging. i put a new alternator in it and it smoked it immediately. then i replaced the starter and went through all of the charging system wires. i couldn't find anything wrong. i put a new alternator in it and it was charging at about 14.5v again. i assumed the starter had a short in it. it ran fine for a couple weeks. i ended up driving it at night again, abd the lights seemed a little dim, but it ran 50 miles in the dark no problem. then a few days later it started running rough and died again... the battery was dead and the alternator was smoked again. put a volt gauge in it and checked it againsy my multimeter and it is spot on, both showing no charging. today i cut out the old fusible links on the starter and solded new wires in their place. instead of another remanufactured alt, i dug through my old parts and found another alternator. i put it on and it was charging at 14.5v again. took it for a test drive and it was acting fine so i figured i would test it... cranked the ac (it still works) and turned on the headlights. it wasn't 30 seconds and the gauge dropped to 12.5v and i could smell the alternator again. killed it again. i am totally stuck... please help! any ideas welcome. thank you.

Usually loose connection at battery will smoke alt in short time