QUIET external low-pressure electric fuel pump?

Noise depends on where you mount them. If on the rear frame rail, with minimal rubber isolators, you will hear a lot of noise thru the back seat. Mine are on the front frame rail in the engine bay and I barely hear them with the engine off and not at all when running. I know many say that location won't work, but works fine for me.

Any EFI pump will supply all the fuel flow you need at carb pressures (~6 psi), unless perhaps a 1200 HP drag rail. If you return to the 1/4" "vent tube" on many 3/8" tank senders, you will get ~10 psig, so you don't need a back-pressure reg for a carb. Use a little in-line pressure-reducing regulator (dial type) to supply ~5 psi to the carb (Mr. Gasket, etc).