It's a 70 truck housing, stock length. I installed it on top of the leaf springs, just had to weld on new perches. It is a 315 drag radial on 15x10 wheels with 6.5in backspace. They tuck real nice!!! I did have to tub it. If you roll the wheel well lips you might can get away with less backspace and not have to tub. I already had the wheels so I just tubbed it to the frame rails.