That will be an easy straight forward job unless you want to revise the housings. 40 rear end, tt, spring and radius arms will fit a 35/6 with no mod. If you are wanting a more exact appearing rear end, then you would have to trim the 40 spring hangers off, cut the axle housing radius rod plates off the 36 rear end and weld them on the 40 housings. The rest of your parts, the controls should bolt up. I believe Ken would be able to do this job well.