I am going to mildly disagree on the need for a regulator. I just checked the factory shop manual for the Rochester 2G series used on mid-1960's Pontiac. MINIMUM ACCEPTABLE PRESSURE OF 5 1/4 psi. Less than that and Pontiac considered the pump defective. When I still had my '64 GTO with factory tripower (Rochesters), I ran better than 6 psi and had no issues. And I regularly run 7.5~8 psi on the 2 Carter AFB's on my shop truck. The issue that MAY cause the need for a regulator is the failure to properly rebuild the carburetor. Each carburetor was designed by engineers with certain design limits. Rochester produced fuel valves for the 2G series from about 0.082 to 0.118. There were also a number of different floats for the 2G series WITH DIFFERENT BUOYANCY! Acquiring a "one size fits nothing" rebuilding kit with a much larger than normal fuel valve orifice will upset the balance of the float system, and then a regulator may be required to prevent flooding. But if this balance is disabled, then the fuel level in the carburetor may vary with RPM. Remember that with a mechanical fuel pump, the pump speed increases as the engine RPM increases. Obviously, not true with an electric pump. Basically, the regulator is a "band-aid". Use the proper parts inside the carburetor, and the regulator, at least for street use, is unnecessary. Please also remember, this thread is about Rochester 2G's, not Holley AA-1's or Stromberg EE-1's. Jon.