Oldbones,
First of all, when you shut it down, does the ammeter show "Zero" or a slight discharge?(Should read Zero; cead-center)
If this is difficult to determine, try this: with the engine off, disconnect the positive battery cable, and touch it back onto the battery post, repeating several times, watching and listening for a small spark.(this may be easier to detect in a darkened garage, or after dark)
If you get a spark, something indeed is draining the battery, and the next thing I would try is disconnecting the wire from the alternator and trying that battery-post thing again; perhaps your alternator is faulty, and draining the battery.
Other possibilities include stoplight switches; I had this problem with a '62 Falcon, and after a legnthy and frustrating search, I discovered that the stoplight switch had "shorted" just enough to drain the battery over several days of non-use, but not enough to make the tail lights glow visibly. I discovered this when my hand brushed against the brakelight switch on the master cylinder, and it burned my hand, it was so hot!
Check other switches such as the ignition, heater,and headlight switch to make sure that when they're "off" , they're really off, and not "bleeding current" out of the battery.
You say you "patched" this alternator into the old harness; did you leave the old regulator in place? If so,did you use any of the terminals as "tie points", and if so, did you connect the alternator to the "Battery" terminal or the "Armature"
terminal?
Perhaps the old regulator is "grounded"?
Start at the battery, and one at a time, disconnect stuff along the way until you eliminate the current drain.
Good luck!
