[Richard]

Was thinking the same as kwmech on a piece of plate if you do not want to move crossmember. You can use a piece of plate or square tube like I did if you need a spacer.
@ mongocanfly, that is a lot of bolts. The 4x4 crossmember in my truck has two bolts at each end attaching to frame. The brace's also only have two bolts on each side attaching to upper frame rails. There are provisions for three bolts on each side to attach brace to crossmember. Do not see room for more than one bolt on either side of the raised portion of crossmember. 4 bolts on each side in my truck.