I have a 92 F-150, extended cab, short bed. I need to replace my front side-mount tank. Do I have the 16 gallon, or the 19 gallon. In looking around for one, some place say the 16 is for short bed and some say the 16 is for short wheel base. But technically I do not have a short wheel base because I have an extended cab. So which is it? 16 or 19?

Never filled it up from E in 16 years? Damn.

"technically I do not have a short wheel base because I have an extended cab"

With such things as measurements, there is no such thing as "technically". What is your wheelbase?

Most junk yards have a parts exchange manual. Otherwise take a tape measure and measure it to be sure it will fit.