Very Confused!

Recently...

My car would keep dying on me, especially when I would arrive at a destination.

...In the parking lot...

I've had to change my alternator, my battery and my voltage regulator recently.

Car is no longer dying but according to a digital reader at O reillys, the alternator is bad again and is going to drain my battery fast.

(This is the fourth alternator, I'm starting to lose my mind.)

Any ideas?

My ride is a 67 barracuda.