I drove the truck (51 3100) to the store last night, and on the way home, I ran out of gas

After 30 years without a stovebolt, you would think that I would remember that those two marks on the gauge aren't for 1/4 tank and 3/4 tank, but since it goes all the way up to F when it's full, that's what I thought. Anyway, after calling a friend to bring me some gas, it wouldn't start unless I poured it down the carb, and then only ran till that was gone. The fuel pump is fairly new, and the PO told me he had this problem. So, my question is, since the tank feeds out of the bottom, I'd like to remedy that, and I'm wondering if the '54 sending units will fit (and work) in place of the bottom feed '51's. The tank is "new", as are the hoses, etc. I don't plan on running out of gas, and wouldn't have if I'd known exactly where empty is on the gauge (I know now!), but it would be nice to think that if I ever do, I won't have to worry about any crud in the bottom of the tank causing me to clean out my system, and call AAA to bring the truck home, like I did last night. A 2 mile trip. SO, will has anyone else had that problem? And does the '54 sending unit, which sends the gas out of the top and has a screen on the unit, work with the behind the seat '51 tanks? Thanks for any help on this, folks! Lee (note: I'll be outside under the truck for a while, so I'll get back in here after while)