I forgot to mark the lines when starting my 350 swap, and I don't know which one is the sending line and which is the return line. There are 3, the little one is for the emissions and the other 2 are larger. Which is which? Thanks, Christian

Do you have two different size lines? If so the larger is supply the smaller is return.

I had the same problem when I did my 350. The return line doesn't go to the bottom of the tank like the send line. Just hook up a compressed air source to one of the lines and if you get air out of the other line it's the return and if you get fuel out of it it's the send line. Just be careful you don't cover yourself or your Jeep in gas while doing it.

Yeah, I decided I didn't want to wait so I figured the return wouldn't run all the way into the tank and that I would try sucking on them to see if I could see which one took more suction since that would be the fuel line. Anyhow, tried the lower one, and just sucked air really easy, tried the upper one and started a siphon, next think I know my jeep was pouring gas into my mouth and all over me. Now I know how my girlfriend feels! :grinpimp: lol