kylightening

pulled my sons gas tank. it is from a 86 f150 stepside that came out as a 6 cyl. now a 302. the tank is rusty and the sending unit bad. but i belive the tank also was changed. The truck in 86 should have been fuel inj. but now carbed. The tank has a 2 prong outlet for the sending unit not 4 like for fuel inj. and only 1 outlet for fuel. Will a earlier sending unit fit or do i get another year tank. It looks like a 84 unit from pics i have seen online. Thanks gary