[67C10Step]

Sorry for the long delay in response to this. Those are the exact springs I put in the back of my 67 for a 4" drop. Photo below. Mine will obviously drop a bit more when I put the bed on it but this appears about right with the 2.5" drop in front that hasn't totally settled out just yet.

I also purchased some shortened bump stops for the rear and there is just a hair over 3.5" of clearance between the stop and the axle housing.