If it's straight out of a Ford pickup it won't bolt directly into a gbody. It won't have anywhere to bolt up to the 4 link and it will probably be too wide. Don't ask me how I know, I already tried one (guy told me it would bolt right in) and when I laid it behind my car (after I already owned it) I realized it was wider than the body of the car.
OP, might wanna measure the width of the rearend and post up pics.