Sounds like a grounding issue - check to ensure that the regulator is properly grounded (bolted to the radiator support) and also check the grounds for the headlights. Since you are getting high voltage, the regulator is suspect if it's properly grounded. It wouldn't be the first time I've seen a bad regulator from the parts store - my old 1972 Impala had the same problem with an Autozone regulator back in 1986 (back then it was Auto Shack, not Autozone for some useless trivia that you'll never need).