[mr48chev]

Here I thought the whole point of putting a flatout C-4 setup in was to get the truck low and have full suspension.

Finding decent photos of the install on the net is a challenge.

Looking at this one that was in Classic trucks way back when I'd say that you need to do about three steps in the planning stage.

First get a crossmember to ground measurement from someone or several folks with the setup instaled so you can get an average to go by.

Figure how high you want it to ride.

Figure out how you are going to drop the crossmember in the frame that amount. That will probably call for adding something like a piece of square or rectangular tube to the bottom rail of the frame as a spacer but will also be longer than the crossmember to act as support on the back side for the C notch you put in the top of the frame rail to clear the back side and maybe both ends of the upper control arm. Meaning that rather than a C notch under the rail to clear the rack you will have C notches on top of the rail to clear the end (s) of the A arms You would want to run the spacer/bracing back several inches past the notch on the back side to fully put the strength back in and then artfully finish off the ends of it so that they looked like they were designed to be part of the install from the get go.