Auto Parts: 1982 4x4 will not charge battery, toyota trucks, gauge wire

Question
i have the above Toyota and the battery will not charge after a new battery, napa external voltage regulator and a Toyota remanufactured alternator to include a new fan belt. I have been chasing wires for weeks, checked all the fuses in the fuse box, new battery terminal post wires. With the truck off I get 11.48 with the multi meter, turn the truck on and get little change in out put. Turn on heater, lights and wipers the multi meter drops into the 10.98 range and would keep dropping if i would continue. I can hook the multi meter up at the ground post on the battery and the alternator B post with the truck running and get 11.17 on the multi meter.    thank you

Answer
    The only thing that I can think of that you haven't already checked is the fusible link(s) attached to the positive post of the battery.  They can look OK and still be bad.  Jumping across them with a piece of 10 gauge wire will eliminate them as suspects.  We had several old Toyota trucks, and charging system problems were one of the few faults that we experienced.  Right beneath the alternator is the brake proportioning valve, and it can, for some reason, cause charging problems.  Another possibility, which isn't as obvious as you'd think it would be, is an oil leak.  When the timing chain gets loose it rubs a hole in the timing cover right next to the alternator.  This sprays oil on the alternator and causes it to cease working because the armature is covered with oil.  The first time we ran into this problem we changed the alternator without looking at the timing cover, and the new alternator failed very quickly.  Check that out, as well, and good luck.