Fuel filler to fuel cell drop ???

[67 455 Bird ragtop]

I poted this on the super fuel cell thread. But I guess that doesn't get much attention so I'll re-post it here.

I have an old plastic Harwood fuel cell I got whan I first stated my rebuild. The name Harwood tells you how long it's been ... LOL. I really don't trust the structural integrity of this cell after sitting around for almost 20 years. When we first started the project the fuel cell hung down below the body of the car. Not a big fan of this. So, I'd like to use a newer aluminum style fuel cell and raise it up so it doesn't hang very much if at all below the rear valance. But, I'd also like to use the stock filler location. So there may be an issue with the slope of the hose between the filler and the fuel cell. What is a "minimum" distance you really need to have between the filler opening and the top of the fuel cell so the fuel goes into the tank and not back up in the hose?? Hope this makes sense .... PS - these are VERY old pics . But you can see how this hangs down. Am I being a little over cautious in not wanting my tank to hang down this much??? I can get an alum that is basically the same size which is what I would really like to use. I don't like the plastic ones.