Half ton

Hello all. I have owned my 1982 f-150 4x4 , it is my craigs list special. I have been experiencing the front tank is slowely putting gas in the rear tank. I know this because i found a hole in the rear tank from rubbing on the bottom a hole appeared and i drained the tank and then flushed with water , but while hooking up my trailer yeaterday gas started dripping out the hole on the rear tank. I did a very temporary fix by clamping the rubber fuel line out of the rear tank with two pop cycle sticks and a pair of vise grips. I ordered a brass manual 3 port tank fuel selector valve and i think this will solve the leak back issue and i believe if i leave the old valve right where it is and just move the fuel hoses to the brass manual selector valve then my dash will still read the fuel level on my instrument panel ?. any feed back if i'm wrong would be apprieciated and thank you !.