Bad Alternator??

Next time, please give us the photo in post #6 at the outset. You also didn't tell us anything about your car, like the year & engine (~1970 in photo?). Is your photo upside down or is the alternator on the driver's side of a slant six engine? If so, it could be a truck setup, but looks more cobbled than that.

Yes, you can switch to a factory Mopar alternator. You can buy aftermarket brackets easy for a small block or big block engine. For a slant, junkyard or ebay. I would get the later "square-back" alternator (bottom left photo of post #4) and a later Vreg (triangle plug). You can mount the Vreg near the alternator, like I did in my 65 Dart, for simpler wiring. Ground the body of Vreg with a dedicated wire, unless you like to rely on rusty sheet metal screws and getting stranded on the road as a result.