Like Jerry said, without the correct tools your shooting in the dark. If you have a meter check your current battery voltage...write it down. Turn on headlights etc. and drain some juice out of the battery. Take another reading at the battery and write down the voltage. When you crank the truck your going to draw your battery down even more. With your meter hooked up watch your voltage and you should see an increase. Increase your rpms and watch it.....you should see an increase in the voltage. If not your probably not getting charge into the battery.

The original charging system is pretty straight forward. Your generator has an armature, field coils and brushes. You have a external regulator that controls the generators output. Any charging system...alternator or generator must have proper grounds and connections. Thats basic stuff. There is nothing wrong with the original system if its built correctly....CORRECTLY being the key word. Any rebuilder is going to do just that....rebuild, with good used parts. I NEVER use a used armature in my restorations..its a waste of time, you can test them on a growler etc. and they may test good...even test good on the test stand, but as soon as you install it, the unit goes south. I always use NOS or rewound armatures to my specs. With that being said I would be curious as to what your rebuilt generator consisted of internally. I would take it off, find a local rebuilder and have it tested alone after I checked the ground, especially to the regulator.

An alternator isnt always a cure all. A standard 10SI, which is the most popular Delco alternator used on these conversions, has a rotor, or armature if you will, stator, diode trio, rectifier bridge with a set of pos. diodes on one side and neg. diodes on the other, an internal voltage regulator and a brush rack. They are very good alternators "if built correctly" and typically last a long time. However, any of the above mentioned alternator parts can fail at any given time. You MUST have a good ground and good connections on an alternator as well.

Alternators are cheaper, no doubt about that as the cost to install new parts in a generator these days is expensive. This all becomes a personal preference and ultimately is up to you. Let us know what you find.
Regards,
Ken

Last edited by Kennethw; 04/13/2016 6:02 AM.