There is a basic geometric formula, but it isn't important to bore you with it this morning. About a year and a half I posted the image below (when I was doing all the fuel gauge work). At some time in the past I posted a chart I made for all kinds of tank depths. I truly wish we had tech tips or some repository in which this stuff could be stored to make it accessible, but that's another discussion, I suppose. Anyhow, there are only two things about the pivot point drop and swing arm length for the behind-the-seat AD tank you need to know: with either the OEM sender or any of the aftermarket senders, the distance from the top of the gas tank to the pivot point will be 5.5". The OEM sender angled backwards, but it didn't change the depth of the pivot point (and this formula...half of it anyhow is simple...the tank is 11" deep so I expect you've already leaped ahead to that conclusion). The length of the arm will be 6.5" long with the OEM sender (because it pivots further back) and 5 7/8" for all others. Unless you're using those figures, your float can't work properly. Good luck. And please say a prayer for the return of usable tech tips.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
