Okay, to start with I have a 1991 F250 with a 300ci six banger I've had about 2 years. I've read about the 3G at alternator conversion and had planned to do it some time in the future.
Then I had a problem 😡
Going back about a year, I had a battery drain issue that was driving me nuts, if I let the truck sit 2 days it needed a jumpstart. I final got that figured out about Feb of this year. Turned out to be a fuel pump relay that was sticking closed and send juice to the fuel pump all the time. I fixed it and everything was fine until 2 weeks ago.
Needed to jumpstart the truck, weather was nice and I've been riding bike a lot so it had sat about a week. Pissed me off. So I started working on it and I found the wiring from the alternator had rubbed against the intake long enough that it wore though the insulation and grounded out. Couple inches of wire cut out and some butt connectors later and it was all good again. Then I thought now is the time to look into the 3G conversion.
So I was at Pick-n-Pull for something else and went to the truck/van area looking for a 3G and I found one that looked right, 2003 E150 van with a 4.2L V6, and 2 bolts, and some cut wires later I had it in my hands.
Trip to Napa Auto during the week to get 3' of battery cable and a fuse holder and fuse and I was ready. So today I pulled the old 2G out, removed the wiring for it. Using the plug from the 3G I built a new wiring harness, then cut the battery cable to length and soldered on some ends, 1/4" on one end and 5/16" on the other, and a short cable with 5/16" on both ends to go from the fuse holder to the starter relay.
After that was done I put the 3G in using the old 2G bottom bolt and the top bolt that I kept when I removed the 3G. I had expected to do some grinding on the bracket that I have read that many have done, but I was lucky and it fit right in without any. I also left the bigger pulley on for now as I did all this at my girlfriends place and didn't have a puller available, I will probably do it later, although at idle it still puts out more than the 2G even with the bigger pulley.
All in all it was a very easy and well worth the time it took, at idle I turned on the lights, w/s wipers, and rolled the power windows up all at once and the needle barley moved.
My ol' truck lives again!

3G with its bigger pulley


Fuse holder to the right of the starter relay. Can ya tell which wires are new? LOL

 

Good data-point. I've never heard of anyone using that alternator, but it sounds like it was a plug-n-play fitment.

Good approach with using the Mega fuse. I had considered that, but since I had the complete dual fusible-link harness from a '95 4.9 F-150, I just went with that, knowingit would fit exactly.

 

I had seen enough pics of one that I just quickly walked down the rows of truck hoping to see one, and when I found this one I pulled out my phone and double checked, knew it was right, but I think I got lucky with how easily it went in.

I didn't have the time that day to trace and separate out the wiring in the van, if it would have worked, and had already figured I would have to build one. And on the hopefully rare chance it pops the fuse I think it'll be easier to replace it on the fly, or take the chance and bypass it. But I'm not going to think I'll ever need to, like your fuseable links, the original one in my truck was in there 28 years. 😁

 

A lot of cars used the same alternator too, so if your yard does not have a big selection of trucks for example, lots of Taurus', Mustangs, etc have the 3G's.
Yours looks to be the 130a version, with it's two holes in the webbing area of the casting. Even a 95a would be great, but yours should work fantastic!

Hope it lives long and prospers for you. Heck, even with it looking a little long in the tooth, the junkyard version will probably live longer than a new one!

Paul