1987 Chevy suburban not charging problem

[KennyB49221]

Hey everyone, Im new to this forum and I know a little about electrical but and not an expert or anything. So heres my story.
My alternator was replaced but was charging during driving and my battery died, so i had it tested on the truck it was only giving 11.6 volts and not may amps. I had it tested off the truck and it was fine they said ( at Autozone). my battery is new. I got into it with one of the guys at the zone and finally he let me replace my alternator again with a new one. Same problem, not charging. Ive checked grounds , replaced my ground battery wire. Im thinking of replacing the wire to the alternator from the battery (+). NO fuses are blown, unless there is one inline with the wire from the harness to the alternator. it looks like that wire was repaired by the previous owner anyways. Also the truck has only 90,000 miles so im thinking this is a older engine b.c its carburated. Are there older sub. engines that were externally regulated with a voltage regulator. Please help. P.S. I also repaired the wire from the battery to the starter. The truck starts fine, just wont charge when running. I dont drive far could that be a problem too?