I am putting the TPI pump in my tank in preparation for an LT1 swap, I almost have the tank out, and while under the car yesterday I saw 4 lines coming from the gas tank.
1. is obviously the feed line, as it is much larger in dia. and runs directly to the filter. It has a soft line on it, but it is crimped on each end. Do I need to replace this, and if so, with what?
2. seems to be a vent? It runs to a small white plastic piece that looks like a single line filter directly in front of the tank (I assume this soft line can stay)
3. Is the return line, it appears to be held on with a screw type hose clamp, does the return soft line need to be replace, and if so, again, what part number do I need to look for?
4. I have no idea what this 4th. line could do??? All told, there are 3 hard lines attached to these 4 soft lines.

Once I get these lines dealt with, the delivery lines that come out under the fire wall are the last two soft lines I saw, is that correct?