I got a 1991 B350 camper van that was previously converted to propane. I want to convert it back to gasoline. I got the throttle body injection assembly, a used fuel tank, a new fuel pump assembly, and new filler neck.

Step 1 is trying to figure out what all the holes are for:

1. Big hole on the side is obviously for the filler. I think need a "filler neck seal" to connect it.
2. Smaller hole to the left of the fuel pump assembly I assume is for the filler vent? Does anybody know a part number for its seal?
3. 5-pin plug. Wire dangling on my van will plug right in.
4. White nipples with the blue caps. I think these are fuel send and return? I have 3 hoses dangling from my van, just need to figure which is which.
5. White nipple pointing straight up with no cap. Not drilled through, so I assume it is unused?
6. What is the large hole with the black grommet?
7. What is the large raised white plastic hole?
8. What is the other thing on the far right with a hose still connected to it?

Thanks in advance!!! I have searched all over and I can't find a basic diagram.

 

Now I am wondering if I have the wrong year tank or wrong fuel pump assembly... I think the valve on the far right is a rollover valve, but there seem to be some diagrams showing a rollover valve installed in the fuel pump housing assembly.... Same with the filler vent. Some fuel pump assemblies come with a big metal pressure regulator, but I have a pressure regulator on my throttle body with a return line....... This shouldn't be rocket science -- if I somehow sealed most of the holes I could make it work but there must be a way with the correct parts!!!