[Singleton]

Originally Posted by GOAT WHORE

I have a 462 with Edelbrock D ports and old faithful roller cam. With stock fuel lines in my 70 GTO I could run the bowl dry on my quadrajet. Going to 1/2 line cured that.
So now I have 1/2 feed line and stock return. Holley 950 ultra hp and run a roddmc 550 pump and pick up. If I go up high in elevation and its hot out the fuel will boil right in the bowls and out the vent and flood out the engine.
I have a tanks Inc tank with walbro pump ready to go in to remedy this situation. I will also be installing a 1/2 return line as HWYSTR455 has suggested.
Anyway just one more thing to think about.

What you've described happens a lot to me, (and i'm at sea level), and is probably happening to a lot of folks who blame other parts of the fuel system.
This ethanol laced fuel boils at a lower temp, (around 175 I think), than the old gas that carbs were designed for.
The boiling doesnt happen while in the pressurized line, but will boil in the atmospheric pressure of the carb bowl. I have a clear sight glass in my Holley carb, so I can see that it is happening. Happens to me usually after a shutting off the motor after a long drive and a short stoppage/restart situation. Drove to a restaurant with the wife yesterday, and after being there for an hour, the engine was flooded. Kinda embarrassing having to start the engine with a wide open throttle and the resulting smoke. I leave the hood up when I can to lessen the heat soak to the carb.
This ethanol fuel doesn't present a problem for modern fuel injected engines because the fuel is always under high pressure, so it never boils.