No head lights or break lights, power acc fuse melted

[85love]

So quick recap, did a motor, trans, and transfer case swap. Got everything switched over and running then my battery died(at this point haven't driven it yet, still working on it). Tested the alternator, putting out way to many volts, got a new alternator, worked fine. So I had the truck idling then all of a sudden I smelt burning from under the dash, the power acc fuse was melting the spot it was in. So I pulled it, tried a couple regular fuses and kept blowing them. Pulled out a test light and was getting current on both sides where the fuse goes in, my buddy says it's only suppose to get power to one side of the fuse(not sure) either way, then noticed that the head lights weren't working or break lights. But the front end side lights were working. Me and my buddy took it for a drive anyway, noticed the volts kept dropping. Got back tested the alternator, thing was putting out like 30 volts! So I know that's the voltage regulator, but what is causing the alternator to do that, I have tried two brand new alternators from summit racing and both has put out two many volts. So could that be wiring or a ground? Other question is what would make my power acc fuse start burning out of no where? 1985 k10, any thing is helpful, thanks.