[Tinindian6702]

Hi,
I am currently installing a crate engine in a 78 firebird to replace my 305. My question is there is two hard lines coming from the sender. One fuel and I guees the other is a vent of some type. Think it went front to the charcoal canister. No longer there.
Can i eliminate the vent or cut it off at some point? Please let me know what my options are. I don't want to run a line with no where for it to go. Thanks

[yzinger]

in my case (406 pontiac) one line is fuel IN to the pump, the other is a vent back from pump to the tank.

[lust4speed]

I think you are talking about the "vapor return line". This is not a great definition since the return line comes off the fuel pump, and while it does return vapor to the tank if there is any, it's just as much of a fuel return line that allows some fuel to recirculate back to the tank. This is a good thing to have, and might keep you from sitting alongside the road on a hot day in traffic. It's not really part of the smog system at all.

To confirm this, just look at the old mechanical fuel pump. It should have a 5/16" intake and a 1/4" return on it. The return is actually reduced down to about .063" inside the fuel pump which limits the amount of fuel that is recycled.