gas tank swap

89 s15 4x4 4.3l reg cab 7ft. bed. i have found several places to buy new tank online but they say not fit 4x4 . what would be the differance? does anyone know which tank i should purchase? i dont care if its a 13 or 20 gal as long as its for fuel injection with pump in tank. thought about used but not sure on interchange years etc...

89 s15 4x4 4.3l reg cab 7ft. bed. i have found several places to buy new tank online but they say not fit 4x4 . what would be the differance? does anyone know which tank i should purchase? i dont care if its a 13 or 20 gal as long as its for fuel injection with pump in tank. thought about used but not sure on interchange years etc...

If they say it does not fit it will not fit.
Size and shape of tanks may bee different.
Keep looking some place may have one that will fit.

On used the salvage yards have interchange books.
Have them look it up.
13 and 20 gal tanks may have different fuel pump hangers and different straps/hangers.

When replacing tank you may need new hangers or straps as a lot of them are rusted bad.