Alternator swap 4 pin 2pin

[exp500]

I am surprised none of this has been consolidated into a Tech Info post for Alternators.

 

[NoReverseYukon]

You all had me worried that my 2-prong adapter wouldn't work so I just did a test. When idling, both batteries are receiving approx. 13.65 volts. That is at the lower limit, but it is at idle and the dual batteries must also affect the output.
I do get code P1638 every now and then, which is a fault in the generator f-terminal circuit, so it's not working exactly as it should.

 

[NoReverseYukon]

Well, I put the old 130 amp alternator back in and now I get 14.7 volts from it. So @Rocket Man @exp500 were correct - these are not interchangeable, even with that adapter.