What kind of material can I use for the tube going down into the tank. I picked up a 1/2 inch brass bulk head so I need some thing to go from it to the bottom of the tank. I was told not to use fuel line because the outside will fall apart. Can pvc be submerged in fuel?

 

use gates sae 30R10 rated for submersion in all types of fuel.

 

Nylon and HDPE are ok with diesel as is kynar I think. Mcmaster-carr lists a compatibility chart someplace.
I personally went with nylon tubing, compression fittings, elbows and barbs in place of the stock module. No air leaks past the compression fittings
What I have noticed is I inhale air at 1/4 tank and lower. You really need that fuel baffle. I might replumb into the bottom of the fuel pickup module. If you go with flexible lines thats easy enough.
If you use fuel hose be careful the outer cover is diesel compatible as well.

 

I got some nylon 5/8 outside 1/2 inside. It is air brake line. Also got some compression fittings to go into the bulk head

 

There was another thread a few weeks ago where someone used 1/2" PVC pipe. Actually, the thread goes on showing how to use the stock pickup basket, cutting off the stock pickup lines, cutting out the in-tank pump, and then adding a bulkhead fitting and 1/2" PVC. In fact I've been trying to find a free weekend to perform the same modification on mine.

EDIT: Here is the thread: https://www.dieseltruckresource.com/...d.php?t=209727

 

I modded my pickup with 1/2" line and retained the antisiphon piece, and can run the tank way low without drawing air at all. Take a look at my Photobucket album, about the middle of it shows some pics: http://s113.photobucket.com/albums/n...post%20photos/

I modified the pickup piece that goes into the antisiphon puck using a piece of copper tube, then connected a piece of clear poly hose to it which then went to the Vulcan drawstraw top cap I bought. I cut the hard black plastic hose off the Vulcan piece.

I purposely used the clear poly hose in order to allow the pickup assembly to retain good contact with the tank floor with its spring action. I feel using a hard pickup line isn't the best approach because your tank probably expands & contracts with temperature and fuel level changes.

 

I bought the vulcan drawstraw but I use biodiesel in that tank and the rubber is attacked by biodiesel.
Instead of going with any kind of grommet on top I went with a pipe bushing and a pipe coupling to make a bulkhead, then threaded the elbow and the compression fitting into it. You can seal the threads with teflon + 'rector seal' or even black RTV. The RTV may swell a little but it shouldnt leak.

 

I would shy away from the threaded white pvc. I have used it in my fuel tanks in the bed and had several break off. I think I used air break line and compression fittings on one of my trucks for the pickup.