i have a carbed 350 holley 670 carb and have a 4th gen ls1 plastic tank im about to install. Since i have a carbed engine how should i deal with all the evap lines from the tank. I'd like the evap system to work if its possible.
Cant find any posts dealing with carbed engines

 

Evap lines on LS1 are different because they have an electronic purge valve and electronic vent valve and their evap canister was located near the tank as well. What you need is 4 lines coming from the tank.

1 - Fuel supply from the pump.
2 - Fuel return, inside the tank this goes into the bucket where the pump and float assemblies are.
3 - Vent, This is the plastic vent valve near the rear driver side tire on 3rd gens
4 - Purge, the line going up to the evap canister.

You will have to make your own lines to connect to your existing lines. For the fuel pressure you will need hard steel line with fittings.

You can run rubber lines for the rest but you should have a barb or flange on the tank side to keep the lines from sliding off like what is on your original hard lines on your car where the rubber lines were installed.

 

ive modified my fuel pump basket to run with no fuel pump because i have an external mallory pump. ive also removed the regulator from the return line. i added a 97 grand prix level sender with the ls1 float.
I have two wires coming from the pump a gray and a black. i want to just chop these off at the connector where they meet up with the two purple wires. Im not sure if i need that ground wire connected. any thoughts? here are some pics.

i also decided against the evap sysyem and instead will vent to the atmosphere

 

You will still need a check valve (couple of vertical coils in the fuel line) to keep fluids from running out if you get flipped over and use a filter on the end of the vent line as you don't want stuff to get into your fuel system.