Charging problems

When I bought my 68 valiant it only charged 12 and used up the battery on its 3 ride home. I swap on another alternator and it charges now but if I rev her up it pegs the meter so I bought new voltage regulator and still does the same thing.
I guessing that not normal. But at cruising rpms it seems to be in the green.

It's been upgraded to 70's plus regulator and duel field alternator.