Guitfiddler

Hi Guys, looking for some assistance. I have a 2003 suburban. The rear coil springs are shot and need to be replaced. I am a contractor so I use this truck and push it when loading, so I would like to replace the springs with a heavy duty spring if there is one. I have searched on line but I can't seem to find anything that says it will fit the Suburban - would appreciate some recommendations and / advice.

thanks