Flat out Engineering has kits to mount C4 Corvette front and rear suspensions for the '55-'59 trucks, and various other vehicles. The boss Don is very friendly and helpful: when I had emailed him a question about the kit, he called me right back, because he thought it was better to be able to talk about my question rather than email back and forth!
Rear end kits are true bolt-ons, very easy to install, even on a Suburban without removing the body.
http://www.flatout-engineering.com/
