I have been using electric fuel pumps, mostly as a backup system to the manual pump for over 50 years. Through the years I have found that a rotary pump works best because the manual pump can pull fuel through the pump where as other pumps can't.
An electric pump should be placed as close to the fuel tank as possible because by nature they push better than they pull.
Most vehicle made since the mid '60's have a fuse block generally mounted on the inner portion of the cowl. Generally there will be at least one AUX/Access terminal that is hooked to the ignition switch.
I always install a switch in the line going to the pump, that way I can control when I want the electric pump to run.
If the electric pump is going to be used as the primary pump it is a good idea to install an oil pressure switch in the line. However if the pump is only used to prime the fuel system the oil pressure switch will negate the electric pump.
In theory the oil pump pressure switch will trigger at a low pressure, however, by the time the engine has been cranked over many times the oil pressure might not be enough to trigger the fuel pump.
If the electric pump is being used to avoid a vapor lock, the dead engine will loose oil pressure and there-bye not trigger the electric fuel pump... Been there done that.
I use to have a fleet of trucks that had aux-fuel tanks, usually one on each side under the flat bed, (50 gal per tank) We would run an aux tank til it was out of fuel, then hit the tank valve, either mechanical or electric to switch to the other aux tank, at the same time we switched tanks we would turn on the electric pump to get the fuel moving in lieu of waiting for the engine pump to pick up the fuel. The main tank was the last tank because it was the only one to have gauge in it.
I have had three motor homes that that similar fuel systems, the modern engines with fuel injection changed the game, dual feed systems are now the common application on multiple fuel tanks.
