You will need to call Mar-K sales to buy the brackets, they are not on the website. Look at the picture of rear sill part number 100717 to see what the Mar-K bracket looks like.It is about an inch longer and about 3/4" taller than the earlier bracket, and yes the 66 bed sits higher off the frame than the earlier bed. I believe about 3/4" taller. 4 X 4 may be different, we don't see many of those and may be some gaps in our information. Let me know if these brackets seem right for your truck.
Mar-Ktech
