i'm running with twin 40 webers and no regulator ... have no issues and haven't in the past ?? even on an old motor with with twin 40 dellortos had no issues without a regulator ?? when i had the current motor rebuilt and the original fuel pump put back on it had a severe over fueling problem, they couldn't come up with a reason for the pump doing it .... the guys tuning it fiddled around stuck on a new pump and no issue since ... the new pump's been run with twin su's and twin 40's, both on dynos with CO count and al the rest done .... no issues and running spot on ........ try a new pump maybe