I have the same issue, just bought a 383 stroker and added dual quads. I have read where some have had vapor lock problems after plugging the vapor return line and some have done this with no problems. I have also read where some have indicated the line may not be necessary depending on which carburetor you are using.
I have ordered a fuel pressure regulator that has an inlet, outlet and a smaller third port for return. I thought about connecting the vapor return line to this port.
Has anyone tried this? Or is it a bad idea?