I have an 85 f150 with a 300 and someone gave me an alternator for a 90 f450 with the 7.3L and I was wondering if it was safe for me to put it in my truck.
The original purpose for that alternator was for my ford 3000 diesel tractor because the ac generator went out again but it wouldn't fit under the hood. I noticed the one in my truck was small enough to so I was figuring on just swapping the 2 out.
I know I'll need a bigger charge wire to the battery but is there anything else other than that?

 

Try to find out what it is. Google "3G alternator" and "3G alternator swap" and see if your alternator looks like the ones pictured.

 

It's not a 3G it's a P7072 it has a battery terminal and a ground terminal and 2 male plug terminals for the stator and field between. I asked a couple of the pretty smart people at O'Reilly's and they said I'd be fine. Its just an increase from 60-70amps to 100amps