All or nothing alternator conversion

So far as pulsation, you may have hit on a regulator that isn't compatible, or one that is bad. You also may have somehow created a "ground loop" causing the problem. Try running a jumper wire from the ground point on the regulator to the ground on the alternator case. You want a no. 10 or so, or if you don't have, parallel 3 or 4 no 14's etc