Aux. tank sending unit

[FORDification]

As most of you know, I'm planning on using an factory in-frame auxiliary fuel tank as my primary tank. I got started on getting it cleaned up last weekend and decided to test the sending unit....good thing I did before mounting everything back up into the chassis, because I was unable to get any ohms reading other than infinity (no resistance). 4x4x4crewcab just happened to have been passing through town right about that time, and we tinkered around for several minutes testing various other sending units I had laying around, and got the same reading (none) on all of them.

Coincidentally, that very same evening while surfing Ebay, I was amazed to find what appeared to be that same sending unit listed. Cool, huh? Well, I recalled posting a question some time back on the old forums asking if the sending unit for the auxiliary tank setup changed at all throughout the '67-'72 era, and 4x4x4crewcab was kind enough to look it up in his parts books for me and here's his reply (saved here from this thread, for the sake of brevity):

What I see from the book is as follows.

The 1967 under body aux. sender is all by itself and should have C7TF-9275-B on part. 1 year only

The 1968 to 1972 style under body aux. sender can have any of the following #'s on the part: C8TF-9275-A, DOTF-9275-B, DOTF-9A213-A
also
The 1973 to 1979 pickup truck models having (reg cab, 2wd, midship tank only) with
DOTF-9275-B or D7TF-9275-BA should work
also for the 68 to 72 style under body aux. tank setup. The 73-79 is a totally different tank but the sender for the 2wd reg. cab midship application should work according to part number changes.
These are all part I.D. #'s or stamp #'s that would be found on the senders either stamped or sometimes on paper tags wrapped around the tubes.
I can't say the parts will all look 100% the same but according to the Ford catalog any numbers mentioned above (68 and newer) should work in the 68-72 aux. tank setup.
Please compare before installing but this info should be fairly accurate

I took some pictures of my original ('68 or '69) sending unit last weekend, so I was able to compare it with the unit being sold on E-bay, which was one of the '67-only pieces (PN C7TZ-9275-B) mentioned above. The only difference appears to be the direction the fuel line exits the unit. Whereas mine exited to the side, this new piece exited upwards, as shown here:



However, it turns out that the E-bay piece was exactly what I needed to get anyway, since the side-exit of the original has some interference with the e-brake system on my chassis, and I was already planning on trying to find some way of reworking the sending unit to exit upwards anyway. This picture was taken while I was mocking everything up with the auxiliary tank, prior to getting it cleaned up:



So I went ahead and sniped the auction and got the sending unit for $43.

Anyway, I decided to post this information here mainly for the sake of archiving it for future reference and for anyone else researching this area.