I'm not familiar with the external voltage regulator and was wondering... an easy test for charging is to pull the pos batt cable while the engine is running, if its charging it will continue to run. Does this hold true with the external regulator? Reason I ask is my Alternator is putting out 13 at the alt, but my gauge in the dash of my '69 is reading negative. I just put a new reg and same thing. Increasing RPM's moves the needle on the gauge a little in the right direction but still not into the positive side. Where can I place a multi meter to check if I'm actually charging? When I disconnect the batt cable the motor dies. Where do I go from here?