Yeah E that's not right. It's a fuel return line. [/quote]
It's actually a vapor return line. Fuel can run through the line but if there's fuel in it something is likely wrong like a blocked fuel line or clogged separator. [/quote]

You are both right! If vapour accumulates in the top of the separator, then it will flow into the return line. If there is no vapour, the fuel will flow into the return line and the flow is restricted by the orifice. I bought a repro for my 440-6 bbl and could not get the engine to start. Found out it was a knockoff and there was no orifice in the return line. All the fuel was going straight back to the tank!!