Clothes Pin On The Fuel Line?

TrailBeast said
It doesn't/can't but people keep saying it.
It can only drain back from the needle/seat but it's impossible for the gas in the carb to be sucked out.
Heat evaporation is what usually empties the bowls.

An electric pump and fuel return line to the tank solves all the vapor lock and drain back issues.
In RRR's case the check valve just keeps the fuel from running back when the engine isn't running.

I am in complete agreement.

Not a slant six, but an 88 Diplomat with a 318. I have had a continuing problem with hard starting and/or vapor lock, after replacing a mechanical fuel pump that broke the arm, at the pivot. Found I only had 2.5 lbs fuel pressure at idle, and took too long to pump from the tank. Had this problem with 3 pumps from different sources. Checked the FP eccentric with a camera, and it was fine. Turns out all the fuel pumps had excessive free play in the stroke, and not enough "pumping" stroke. Cured the problem by slightly bending the pump arm, to reduce the freeplay. Now have about 4.5 -5 lbs fuel pressure, and no more vapor lock, or hard starting