I installed an MSD HEI Pro Billet plug and play distributor on my 68 442 BB 400. When I put the car in gear the GEN light comes on and I can hear the voltage regulator buzzing, as soon as I give it some gas buzzing stops and light goes out. I have the original alternator that has been rebuilt and a new stock voltage regulator I have the idle set at about 950 to 100 that seems to be where the cam likes it. Do I need to run a different alternator or voltage regulator or both

 

Sounds like a bad voltage regulator and the contacts are chattering..

 

Make sure the reg has a good ground

 

OK replaced the voltage regulator with an A/C Delco D663, ground checked out good and battery tests good but light still on dimly and voltage regulator still buzzing at idle when car is warm. Do I need an alternator with higher output and if so what output should I go to? I have found some on line that can putout up to 120 with out modifying or changing the stock wiring harness.

 

How much voltage is the battery seeing when the car is at idle? And with the rpm's up a bit?