bypass original fuel pump or not

[whatwas]

I moved the fuel tank to the rear of the frame (spare tire area) of my 67 truck. Its the old aux. tank from my GMC 3500 so the electric fuel pump (frame mount) was intended to pump from tank to tank. My question is, do I route the fuel line through the electric fuel pump into the original engine pump or by-pass the engine pump and directly to the carb. My fear would be to overpressure the float in the carb.

[aerotest]

They make electric fuel pumps for carb applications.

[Andy4639]

Originally Posted by whatwas

I moved the fuel tank to the rear of the frame (spare tire area) of my 67 truck. Its the old aux. tank from my GMC 3500 so the electric fuel pump (frame mount) was intended to pump from tank to tank. My question is, do I route the fuel line through the electric fuel pump into the original engine pump or by-pass the engine pump and directly to the carb. My fear would be to overpressure the float in the carb.

Depends on how much pressure you have. The best solution is run a fuel pressure regulator near the tank with a return line. This way you only have one fuel pump.

I have seen guy's run the electric to the mechanical just to prime it then turn the electric off and use the mechanical one but that to me is not the best way.

[HO455]

I would recommend against running it though the mechanical fuel pump for the following reason.
When the diaphragm in the mechanical pump fails (and it will) the electric pump will force fuel through the diaphragm into the engine diluting the oil. You would have no indication that this was happening.
It would be best to buy a pump with the proper pressure and/or install a pressure regulator and bypass the mechanical pump if you want to use an electric pump.
Also depending on your engine combination that fuel transfer pump may not have enough capacity (GPM) to supply your engine.