Ok well here goes a pretty long story. So I've got a 68 Valiant with a slant six in it. One day I left the lights on by accident. I then had a slight feeling that I left the lights on that evening but I brushed it off. Anyways, the next morning the battery is completely dead and lucky I didn't really have anywhere to go so I just took the battery inside and trickle charged it because my dad needed to go to work the next morning and wasn't going to be able to take the car he usually did. It was about 11:00 at night and he wanted me to go reconnect the battery so I did. I couldn't see well enough and it didn't help that both the battery cables are black. Long story short I hooked up the battery backwards and burnt out the fusable link. Me and my dad have already replaced the fusable link with a automatic reset circuit breaker and we replaced any other burnt out wire. I thought were have alternator problems before I hooked up the battery backwards so I took the alternator to get tested and sure enough it was bad. No big deal so we just got a new alternator. The only big difference between the two alternators was that the first one was a 2 groove pulley and the new one was a 1 grove pulley. I fiddled with the new alternator before we put it on and it seemed to work fine like it turned like it was supposed to. Then we installed it.(NOTE:we put in the alternator a few days before we replaced the wiring and circuit breaker). Once we replace the wiring,circuit breaker, and got a new battery we were ready to start it. Went to start it and it made a real loud squeaking noise but you could tell it tried to turn over so it wasn't the starter. I watched it while my dad started it and saw that the alternator was moving at all! THE BRAND SPANKIN' NEW ONE! We took the belt off and just tried spinning it with our hand and it wouldn't budge. Is there anything you can do to fix this or am I better off just getting a new alternator?