I am using the original efi fuel pump and pressure regulator with carbs.

What fuel pressure regulator do I need to come off the existing fuel line to get the pressure down to the carbies requirements?

I guess I can use the existing double relay to power the fuel pump with a few mods.

My thoughts are that you would be better off using a low pressure electric pump 3-5psi rather than the injected pump which runs a lot higher pressure. I also use the cut out relay so when the engine stops so does the fuel supply. this may not be what you want but it works efficiently and does not sink the floats. I know that there are aftermarket adjustable fuel pressure regulators available but i think cost etc makes this unviable. cheers Les

Thanking you. I will go for the 3.5psi electric fuel pump as it seems a better idea.
Regards Tom