So how do you plumb the bypass regulator into the stock fuel lines? Presently has the stock connections under the hood. It's high pressure, so I assume the old school fuel line and hose clamps would not work?
If you are switching to a 5-10psi fuel pressure carburetor setup you can just use the one fuel out line at the top of the tank but you need to remove the in tank pump and replace it with a "pickup hose" connected to a "sock filter" at the bottom of the tank
Yes, cap off the old return line port
You can just use barbed fittings and clamps on these low pressure hoses
Most low pressure electric fuel pumps have good SUCTION, most is the key word, all high pressure pumps have 0 suction
Mechanical pumps that were used in the old days have GREAT suction, so could PULL fuel up and over the top of the gas tank
You need an electrical pump that can do the same
Diaphragm pumps(like old mechanical ones), have good suction but limited output pressure
Centrifugal pumps have no suction but can do high pressure, needed for fuel injection
What others are referring to about using the old return line is if you decided to leave a high pressure pump in the gas tank but want to use a carburetor
You can get fuel pressure regulators that have a return line, mounted in frame rail or at the engine end
It lowers the 70+psi to 10psi and sends extra fuel back to the tank so doesn't put too much backpressure on the high pressure pump in the tank
If you are eliminating the high pressure pump in the tank you won't need the return line
Just as a safety heads up
Electric fuel pumps have a big draw back in vehicles
In an accident they can continue to pump out gasoline if a fuel line should break................usually NOT a good thing
With mechanical pumps if fuel flow stopped, i.e. broken fuel line, then engine stops and so does the pump
With electric pumps vehicle makers usually have two automatic shut offs for electric pumps
Inertia switch, has a weight inside, if weight shifts in a sudden stop or roll over it cuts 12v to the pump
EFI needs a computer, the computer can shut off power to electric pump if RPMs drop below 400, which engine would do if a fuel line broke
You can/should use your current inertia switch
You can also use an Oil Pressure Switch, it unGrounds fuel pump relay when oil pressure is below 5psi, can't use this on an EFI engine because it needs fuel pressure to start up
But a carb has a float bowl so can start up and then the oil pressure triggers fuel pump relay to turn on the pump