need help with 20x14.5 wheel spacing

[ttjordan25]

I have a 76, and am wanting know what is the way route to take with my rear end. The wheels that I have are Coy's 20x14.5 the wheel specs are 10in towards the front and 4.5 toward the back (back spacing?). I've got a 4 link coil over suspension to get rid of the leave springs, but im thinking that the rear end may have to be narrowed? If so what is the best most cost friendly way to get the space I need for my wheels +tires to tuck (rear end swap? or pay to have it narrowed)...I know what the next question will be..."What size tire?" well I havent really thought about this yet (any suggestions). Also the bed will be tubed. Thanks for the help family!!!!