Was running but now after pulling alternator wire, it won’t run
I checked using a multimeter. Alternator is only showing battery voltage. I also did the negative battery cable trick. If you pull the negative and the car shuts off it’s the alternator. Also I don’t have anything going to the voltmeter in the dash.
Please be specific about which wires were checked. It matters a whole bunch. 'alternator shows only battery voltage' doesn't really say as much as one might think.
There's the big charging stud on the alt, and two field wires. The field wires are controlled by the regulator. Depending on which generation of voltage regulator you have and what generation of wiring is in your car, the field could be the whole issue.
Pulling the negative can be misleading. A bad regulator, a bad field wire, or improper wiring could all result in it not running. Doesn't mean the alt is bad in all cases.
Have the alternator bench tested to rule it in/out. If it checks good, we can proceed from there.
In the meantime, do you know if the voltage regulator is correct? Was it recently replaced along with the alternator? Can you take photos and post them of the regulator?
I'm not an expert on the timelines, but Chrysler had a single-wire regulator up until around 1969, and starting in 70 had a 'dual field' style. I've only ever dealt with the dual field style, and many auto parts stores will sell you an alternator for your single field car setup for a dual field regulator. Do a search and you'll find a ton of info on that, but you really need to investigate your car to determine which system it has. It's not uncommon for previous owners to have swapped out to the later style at some point in the last 50 some years.
As others have said, there's no reason for the alternator to have an impact on whether the car will start and run unless something was shorted and caused a problem. I don't like disconnecting the battery from the system while it's running, especially with aftermarket ignition, because I've seen that result in hard to trace damage in the past.
For now, I'd bypass the MSD using the factory ignition and see if it suddenly runs again. MSD doesn't have the greatest reputation for reliability these days.
