It has been a long time since I messed with this stuff, and much has changed. I need a new fuel pump for my modest 355 SBC w/carb project. My 84 C10 w/carbureted 305 has 3 lines connected to the stock pump. Do I conclude that the 3rd line is a return? Many sellers show 2 line and/or 3 line pumps, but no mention of that is found in descriptions. I would have to believe I need a 3 line pump?? BTW, what does the charcoal canister do? Mine has been disconnected from the vacuum system. Do I keep/replumb or remove?