Originally posted by HighSchool hauler:
Are these original or could they possibly be off of a different truck?
HighSchool: I have not seen the shorter 'reinforcing strips' used originally on any shortbed trucks of your year series. Perhaps other readers have different experience. If you use them, the only problem you might find is on the row of bedstrip bolts directly over the frame kick up area. The reinforcing strip may contact the frame.
46forme is correct, the wood blocks go under the cross sill where the bed to frame bolts go through, so the bolts go through the bedwood, cross sill, wood block, and frame rail.
http://www.mar-k.com/bed_mounting_information.pdf Here is a brief description of the mounting for your bed.
Keep us informed how your project works out.
Mar-Ktech