I just installed an Accufab fuel pressure regulator and it seems that the brass nipple fitting for the vacuum line is too small in diameter to hold the stock Ford regulator vacuum line. The line fits the stock regulator as well as the Kirban I just replaced with the Accufab, so I know the line is not the reason. If you are running a FREG, please tell me if you have had the same problem and how you solved it. I contacted Accufab and was told that they have been using the same brass nipples for 10 years with no issues.