Thanks for the replies guys. No one ever helped me out so I bought a CST 4" lift spindle kit and block kit for the rear.
The front shocks were definitely stock since they had the factory part number sticker still on. They also measured the same length as stock replacements that I checked on. I really am stumped and I have been working on cars for over 30 years. All the part numbers check out, the factory rubber spring seat was removed when I installed the spacer, and the springs were seated correctly in the upper and lower arm. They simply maxed out the travel. Anyway, here is the truck today with the CST lift spindles: