On '63-72 trucks, the installer has to knock this crossmember rivet out and use it as the rear mounting position for the sway bar bracket. The rivet is located just to the rear of the front of the frame on the first crossmember. It's easy to knock out with an air chisel. Another option is to cut the rivet down the middle with a cutting wheel and break the head of the rivet off. From there, drill a hole in the front mounting hole and install the mount using the provided hardware. The sway bars can also be installed like this on post-'72 chassis as well. That's actually the road we took. We'll get into the reasoning behind that in a little while.