electric vs mech fuel pump question

How well does an engine driven pump (F-head, non military pump - no vacuum) pull fuel through an electric pump, for example - a Holly "red"?

I have a 1953 M38A1, stock F head, original fuel tank under the driver's seat. I am thinking of adding another tank under the rear compartment which would probably require a boost pump to feed the engine driven pump. I have a selector valve to use between the seat tank and the aux tank. I have considered just eliminating the engine driven pump and plumbing in 2 electric pumps. Any thoughts/ suggestions?

Thanks,

g

 

2 thoughts-I have both front and rear tanks with the stock mechanical pump-it works just fine.
Secondly, some electric pumps allow fuel flow when not running and others do not (IIRC the Holley pumps don't).

 

one electric fuel pump or one mechanical fuel pump and a switchable T in the fuel line just in front of the seat tank, with the rear tank on the opposite side should work just fine.

 

If you run the electric pump You should run a fuel pressure regulator. running the fuel through a stock pump is not a good idea. Run the new pump out hose to the fuel pressure regulator the carb inlet.

 

My mechanical went out, and another was not readily available in my area, but the Mr Gasket low pressure (3 lb) electric was so I plumbed and wired that in place of the mechanical. The low pressure pumps don't need pressure regulators.

 

Thanks guys. I'll try it with a switchable T and the mech pump.

 

Generally, the gear type pumps, including Holley's, will not allow "suck through". Most diaphragm style pumps will. I ran both a mechanical and an AC electric (diaphragm) on a single line in the 3B for decades. Built-in backup. The combo produced about 15 psi which I knocked back to 8 with a regulator. The system was only discarded when the FI went on.