won't charge

[DADS67]

I have a 289 '67 that is driving me crazy with electrical problem..specificaly charging the battery. The car will run with a dead battery (does this mean the alternator is OK?) I have charged the battery, but when I shut the engine off..no juice. I have changed the regulator. No charging. I placed an after market Ammeter. No change + or -. I have established power out of the alternator. I seem to have power from the solenoid back to the battery. The guy I bought the (as is) car from sais he put a new alternator in after someone switched the cables of the battery and fried the alternator and battery. Is it possible soimething else burned? I think I have traced allthe wires. Like I say, the car runs great, starts easy, but no charge goes back into the battery. Could it be as simple as a bad battery? (the battery drops about 75% after each strt and re charges VERY quickly). Thanks.