I've got a rail mounted Mallory 4212 AFPR and I noticed recently that my vacuum was a couple of psi low and my fuel pressure was right around 40 psi at idle. It would increase linearly under boost, but was not dropping below 40 psi when decelerating or idling. I tested the vacuum port on the AFPR and sure enough, it was leaking vacuum. Ordered a rebuild kit for the AFPR, but have a nice OEM regulator that I can drop in for the meantime. Is there really any kind of flow difference between the 2 FPRs since they're both rail mounted anyway?