This is how I have done them, 5-ton front springs, custom made u-bolts, and a spacer about 1.5" tall. Blocks are never an ideal solution for any suspension problem, but when kept below 3" they aren't too awful bad. On a heavy duty truck like these I personally would not want to use a block taller than 1.5"-2". Blocks contribute to axle wrap, so with the weight/torque these trucks put out coupled with 8" of lift block AND springs too light for the job (m105 springs) bad things can happen. 8" blocks would have very bad axle wrap even with the 5-ton springs.
Sometimes it takes a friend to talk you into something stupid, but there are also times friends talk you out of stupid things too!!
I am honestly surprised that the inspection stations failed it, I am GLAD there are some stations out there that actually still do a good job of looking at stuff like this! (assuming they all failed it because of the blocks).
View attachment 481185View attachment 481186