I ran some spring spacers on my first car to give it that hotrod look. They were some screw looking devices that were square, started out small and as you twisted them in, got larger for more lift. Didn't seem to change the ride any.
Ahh, found a pic:
However, I do have to agree with others in that there are likely other issues causing the lean. I would think you could quickly determine whether it was a suspension problem or a body problem by laying a level across your frame.
Other places to look is to make sure the C-bushings on the front axle are installed correctly. Do you have a rear locker? Sometimes when they are in a bind (parked with the wheels turned) they can cause some suspension bind and make the bronco lean, but that would be dependent on which direction the wheels were turned.