You have a short to ground, probably a pinched wire in one of the circuits that the 12 gauge accessory wire feeds.
Pull the negative battery cable off and connect a test light or a multi meter between the battery ground post and the negative cable. See if the light lights up or the meter reads more than 3 milliamps .003. I suspect that you won't get a reading until you turn the key on, and then it will exceed the 10 amp maximum setting of the meter, so you don't want that, or you might damage the meter. If you use a light then you should first remove one of the fuse panel fuses, then quickly turn on the key and watch for the light to come on. If it does then quickly turn off the key and repeat the process with the other fuses one at a time until the light doesn't light. when it doesn't then you will know which circuit the short is on and you can trace the wires in that circuit until you find the pinched or shorted wire.
If the short is not fused or if it is ahead of the fuse, then it may not blow any of the fuses, which should have already been blown if the short was after the fuse.
The accessory wire powers the wipers, the heater switch, the turn signal flashers, and the hazard flasher, the turn signal switch,and one other thing. I'll have to check.
You might also have forgotten the 700r4 compressor clutch switch wire, which is hot with the key on. It may be touching a ground. See if the clutch power was taken off the fuse panel from one of the fuses or from the IGN Unfused terminal on the panel.
The hard starting is probably caused by the large drain on the key ignition wire, and causing low voltage to the distributor. If you still have points ignition you will get a full 12 volts bypass to the coil, which would let the engine fire, but when you release the starter, the drain on the ignition would cut the voltage and cause the engine to die or misfire.
This thread will probably get moved to the electrical section where it should have been posted so I will monitor that.
Here's a diagram with the accessory wire marked with the black arrows.
It also powers the backup light switch fuse.
