fuel tank size ?

[Sublime]

Is it possible to have a single 20 gallon fuel tank on a 1978 stepside. Everything I have read states stepsides should have a 16 gallon tank.
I ask because my fuel gauge read 1/4 tank when I filled it, it took 16.1 gallons. Are there any numbers on the tank that tell it size. Does anyone know dimensions of a 16 vs a 20 gallon tank?
Thanks

 

[74 Shortbed]

Could put a Suburban tank in the back.. Since I won't be using the bed for hauling I'm gonna put a custom 25gal tank in the bed in mine.

 

[Sublime]

I am wondering if a 20 gal and a 16 gallon tank look similar and both mount to the outside of the frame rail. I am trying to decide if my fuel gauge is correct. If I have a 16 gallon tank then it is off. If I have a 20 gallon tank its right on.

 

[74 Shortbed]

They look the same just different lengths, I don't think the 20 fits a shortbed, got this from LMC..

 

[Sublime]

Thank you, my searching skills need help. I looked on LMC and completely missed that.
So I have a 16 gallon tank that needs a new sender

 

[bucket]

Even if you did have a 20 gallon tank, you would still need a new sender. Both tanks are the same depth, so the sender is correct in either.

 

[RThiel]

^^^This. It's not your tank. Either your sender is off or your gauge is off.

 

[Keith Seymore]

SWB only got a 16 gallon tank, because of the vehicle length.

LWB could get a 16 gallon or 20 gallon depending on the GVW rating of the truck (carrying the added fuel affects the available payload).

K

 

[Sublime]

Thanks all, I replaced the sender. I now have reliable fuel gauge readings.