When I installed my bed, I had to cut down the front blocks to make the gap right. On the rear I bolted the cross member to the frame without any type of spacer.

1950 Chevy p\u 3100. lt1 Corvette powered.
Owner\ autoglass unlimited/Ultra Clear Body Shield
Cowboys creo: taste your words before you spit them out
http://s202.photobucket.com/albums/aa180/getm24_2000/