I made new tests with the pump connected to the fuel tank on front of the vehicle, it was able to dump 1 liter in 40 seconds, that's 1.5 liter/Min about 24 GPH, i just routed the mechanical fuel pump inlet and float bowl output line to a fuel container to keep flow and prevent damage, the accelerator pump line was left in it's place, i routed a hose directly from the electric fuel pump to the float bowl connector only with no regulator, no overflow happened, and the engine runs ok, even if you increase RPM's, when the engine is idling if you turn off the pump it takes about 90 seconds for the engine to shut down.

Need to make a new test with the electric pump completely installed and check the vehicle under load, can i keep the mechanical fuel pump with no fuel and use the vehicle for a while just for test purpose?

Maybe i can connect both output lines of the fuel pump to a "T" and a hose filled with fuel and connect it to the pump's intake so it works with some fuel.