Stock fuel tank and EFI - did you make it work?

[boneheadzz]

Just like the title says. I am tempted to try using the factory tank with the new-to-me Commander 950 kit I have. It needs to use a return line and my 79 Trans Am has a 1/4" vapor line (which I believe is too small to use) and a larger vapor return line that runs from the charcoal canister somewhere on the passenger side up front and back to the tank. I was thinking of using this for a return. It looks like it dumps into the tank via a welded/soldered(?) line independent of the fuel sending unit. My fear is that it just goes into the tank and basically just dumps vapor or in my intended use, fuel, causing splashing, foaming and adding air to the fuel.
Anyone try this?
Or other suggestions?
I've seen the moroso kit where you cut the filler neck and hose clamp in a section of tubing with a welded in return line. This is probably the option I'll use but I was curious of this spare line that as far as I know, no one uses.
Later!
Mike

p.s. I did find some info in the install manual for the system:
"8.8 Return Line Installation
The Holley COMMANDER 950 TBI system requires a return fuel line to the fuel tank. Some late model vehicles that were originally equipped with a throttle body injection system may already have a return line to the fuel tank that
can be utilized. If a return fuel line must be installed, a minimum size of 5/16” I.D. is recommended.
DANGER! DO NOT USE THE VAPOR CANISTER LINES AS A FUEL RETURN LINE. POSSIBLE FUEL LEAKS MAY CREATE A FIRE OR EXPLOSION HAZARD, CAUSING SERIOUS INJURY OR DEATH."


OK, not that I'm smarter than the Holley engineers but I believe this is lawyer speak for 'We're not liable!'. But if this line were properly inspected, clamped and sealed... it should work. Or am I pushing my luck?

[Jetfixr320]

My guess is, Vapor line is just that vapor and low to no pressure.
Your return from the engine will have some pressure behind it. I think I would find another source.

[boneheadzz]

Yeah, I started thinking more about it and came to the conclusion that the vapor line is essentially a vent. So I'm off to order the moroso kit then.
Thanks for your input.

[Ollie8974]

Don't use the vapor return line as a fuel return line.
There is a one way check valve in the tank, that only allows fuel vapor to be drawn into the charcoal canister.
Save your money on the Moroso kit.
The fuel return line from the fuel pump is 5/16, can be used as the fuel return line.

[chevnut55]

I used the filler neck for a return on a 67 Camaro, on a 72 I drilled and taped a fitting near the top of the tank.
on my 69 I used a tank from tanks so it was bolt in and go.
I did use the vapor line before but I think I messed with the sender so it was clear to return fuel and it was hooked at the firewall back not going through the canister.