use your newer square back alt,and get the correct regulator and 3 pin plug,, all you have to do is add one wire,,from the alt back to the new regulator,,
the advantage of the newer charging system is,besides better charging is,,when you are at idel at a trafic lite at night with your head lites on radio,foot on your brake,,ever see your headlites flicker,,brite then dim,,,that is the old style regulator doing that it doent charge at idel,,only when you raise the engine rpm...the new style regulator is a constant charge,, then delete your amp gauge,and install a volt gauge,,the old amp gauge wil not take the amperage of the new altenator,,and it wil either short out or it will quit working,,if it quits working the car will not start,,the complete car is running thru that amp gauge,,