1 you need your exciter wire hooked up(correctly, find the right wire, put a connector on it, hook it up, not difficult)(maybe you need to add a length of wire to it, as it may have been cut, can use a connector, or solder) with out the exciter wire i figure the current in the alternator is backing up, get it working correctly, dont run till you get red warning light on the dash to go out.
another these days we have to keep our pulleys, esp from the alt. if you have A/C its imperative, the reman or new alt they send you have some type of pulley on it, you have to swap in your old just used pulley. otherwise it may not line-up correctly. finding a pulley at a store can be impossible and a little expensive, that is IF you can find the correct pulley to fit. like $45 or so for a pulley you could have just pulled off old alt before you core it.