I can find countless information on NBS Ford Hutch/Harpoon Mods but none on OBS Fords. Just curious why that would be if anyone knew? Since I couldn't find any information for an OBS Hutch/Harpoon mod I just took the principle of the NBS mods and applied them to the OBS design. Here's my version of the Hutch Mod.

All I really did was cut a piece of 3/8 fuel line and pool clamped it to the end of the sending units pick up tube and just kept fitting it in the tank and trimming the fuel line till it had about 1/4 - 1/2 spacing between the line and the bottom of the tank. I didn't bother with a screen or anything for the pick up tube because I'm doing the Electric fuel conversion which will have two fuel filters to catch any debris instead of letting it just build up in the tank over time. Fuel filters are easily replaced while dropping those tanks to clean them out is not easy. I also routed the return lines in a similar fashion with 3/8 fuel line and and 90 piece of stainless fuel line I had laying around to get the return fuel away from the pick up. I heard somewhere that routing the return line away from the pick up was better for some reason...is it true??? No idea but can't hurt.

Now I haven't done the Harpoon mod yet as I'm not 100% sure it's going to work Like I think because my knowledge on filler necks is next to none. My initial thoughts are that the smaller tube (Last picture with arrow pointing to it) that runs down the center of the other bigger tube would be the vent tube that causes the pump to click off before it over flows onto the side of your truck.....so with that thought I was just going to cut that smaller center tube so that it is only a 1/2 inch or so longer than the bigger surrounding tube. Does anyone know if that is how the filler neck works on these OBS Fords and if that is how we could benefit from a harpoon mod of this matter as well?

Let me know what you guys think!

 

The small diameter tube of the filler neck is what fuel flows through. The vent is the space between the inner and outer tubes. Adding an extra vent to the tank and removing the inner tube of the filler neck is what I've read to do for diesel trucks to enable you to use the big rig pumps.

 

Gotcha, so I'll just leave that hose the length it is then and let it be with the hutch mod. Thanks!