You mean a "3G" I expect. I'm big on 3G's and put them in all my Fords that didn't have one from the factory.
I've not kept an ammeter though. I don't like them nor the limited information they convey (in stock form anyway). The ones I've dealt I simply bypassed and/or replaced them with voltmeters.
Depends on what alternator you have now. If you have a "large case" 1G then you want a box like this: https://www.paperformance.com/1g-3g-conversion-462802c/
If you have a 2G (I doubt) then Google swapping to a 3G is a lot easier.
If you have a Leece-neville or something than I don't know but someone out there will.