So i bought a new alternator and ever time i hook it up it grounds out but the old one doesn't. would this be a bad volt regulator or a bigger problem. the alternator that i bought it a durlast one from autozone

 

I may be wrong, but 79s had external voltage regulator and newer were internal, may just have wrong one,

 

the one that i bought runs off the external one that's what they told me at the store. its the same make and look just like the one i took off