Ok so all is well with my rebuild and noticed battery was a little weak on startup. Then went dead after attempting to start up.

I busted out the battery charger and left on for a bit, car started up but readingn 10.8 volts while running.

I noticed an orange wire that leads from the alternator to the volt regulator came off the connector and was touching the chassis. Anyone know what this wire is for? Could this be my problem? It's too late and dark out to be playing with wires....

 

With that vintage mustang it is hard to say. As cars get older and people replace wires with what they have on hand, it gets tricky.

But 10.8 volts is definitely low. I would have your battery tested. You may have killed it by letting it loose too much of a charge. You also don’t want to run with a bad battery for too long because it can burn up the alternator. Most auto parts stores will test your alternator & battery for free though. You might want to give that a try. Good luck...

 

Ok so I fixed the problem, the wires needed replacing from the regulator to the solenoid. Changed the wires and now at idle it's 12.80 and as it
Revs it goes up.

Thanks for the help, another problem solved!