I have a 66 Suburban that I have recently taken this apart, and yes it does have the wedge shaped block, and no, it does not have any threads. The wedge goes on the rod with the pointed end of the block, pointing toward the rear of the vehicle. The rod goes through the fork, and the wedge fits into the vertical groove in the fork. The rod is long enough, that it will not come out of the fork, unless you have major problems.
