can i put 20 inch dodge ram wheels on my 91 dakota sport 4x4, they are both 5 lug, but not sure if the same size, does anyone know if they will fit?

 

Your '91 Dakota should not have a 5 lug pattern! '91 all the way through the end of the 2nd gen Dakotas had a 6x4.5" pattern. But, if yours happens to be the pre-91 lug pattern for some reason, its a 5x4.5" pattern, which is smaller than the Ram.