if chevy springs are the same width as fords and are mounted the same distance from the frame, you could probably do your flip like i did with the stock f250 hanger and gain 5.5" lift. i spent under $50 and it's as strong as the day it left the factory:
why are they not rec. for towing? at least on mine, the side-load physics are the same and it should be as strong as the stock setup.