2nd Gen Non-Engine/Transmission How much usable fuel in a stock 34Gal tank?

[bramage]

I've had 3 different Dodge/Cummins 96 Ext. cab 3500 2wd, 97 Ext. cab 2500 4wd and my 98 Quad Cab 3500 4wd. All have had the same fuel tank. I haven't run this one out yet (don't plan on it either) but I ran the first one out several times due to a bad sender in the tank and I ran the second one out once or twice due to stupidity. The '96 would take just over 36 gallons after it died but the '97 would not quite take 35. 5, if I remember right. Don't know why there was a difference but the only thing i could figure out was a difference in stance. (Angle of truck from front to back not height. )