Yeah it was just bad luck. I asked the technician if I had it wired wrong and he said it would be much better to use the battery as a source for the HEI and not the alternator, but that no, the alternator just picked that day to die.

I found out the alternator was out of a 1985 Buick Electra and was a 108 Amp, but he souped it up to a 120 Amp while he was at it, which is cool. Now I can run A/C and an electric fan if I ever want to.

So anyway, I'm going to rewire that circuit while I'm at it.
Thanks for all your help.