Alternator not charging battery

[1969CoronetR/T]

My battery barely started my R/T today so I drove it to downtown Pittsburgh for a family friend mechanic to look at it in his garage. He checked the regulator and found out the alternator was not working. I went to order a new on from summit and have to decide between two different models:

75 amps, external regulator, double groove pulley (seems identical to my OE)

or

100 amps, internal regulator, single pulley

Would the internal regulator clean up the wiring for my now external regulator on my firewall? Would a single pulley work since I have a double pulley although only one groove being used on my defective alternator?

Thanks,
Mark

 

[dpstark2]

You may know this, but just in case- If you use either of those, you will need to look into bypassing your ammeter. If you don't, there's a good chance you'll quickly fry your wiring, possibly starting a fire.

Either way, an external regulator is generally better if you don't mind the clutter. The internal regulator version typically do not turn on until 1200 or so engine RPM, which means you won't charge much or at all at idle. I currently have this issue, and I would go back to external if I could. Oh, and I guess I mean a "1-wire" ammeter with internal regulator. There could be an internal regulator version without the "1-wire" feature.

I'm not sure if the double groove pulley actually lines up with the single groove, but I've seen plenty of people "make" it work.

 

[1969CoronetR/T]

I found one that is a double pulley groove with an internal regulator and is one wire capable.
http://www.summitracing.com/parts/pwm-17509/overview/

and
http://www.summitracing.com/parts/pwm-175091

Can the old alternator be rebuilt?