I have an '86 Bertone in pretty good shape, but there are some issues. First thing in the morning, it can takes about 15 cranks or a push to start. After that, it will run great- BUT after warming up, the volts & temp will simultaneously go awry. Any ideas? I'm thinking the alternator & water pump might share a common belt, but that's just a guess. Any help will be appreciated.

The problem is almost undoubtably to do with the wiring and is likely to be two fold.

1) The earthing in the engine bay needs checking and reseating - odds are that one or more straps is broken and the chassis earthing points need cleaning up to ensure that the electrics have at least a chance of working.

2) The cabling from the battery to the engine is degraded, it is just one fat red cable but in 24+ years it has increased in resistance which means when cranking the engine it doesn't get 12v, you will probably need to replace the not quite so fat brown wire into the fuse box as well and you'll find everything works better.

These are pretty wild guesses but almost every car I know of has needed these repairs by the time the car is 30 years old. Try looking up the brown wire mod in a search and you should find instructions and other general related advice.