[mdross1]

Fuel pressure dropping to zero means the needles are off their seats or at least one of them is.Naturally the pump is going to do it's job and overfill the bowls with nothing to stop it.You might talk to Holley about the zero fuel pressure issue
My 460 with 850 dbl pmp Holley regulated to 5.5lbs and water temps at 190+or- never gives me any problems.