Belltech 6636 is a shackle and hanger kit. shows the same shackles as any other 400. I've never lowered a Tahoe, so I don't know about the clearance.
http://www.belltech.com/products/belltech/rear-lowering-components/shackle-hanger-kit-16.html
The instructions make no mention clearance issues. (obviously)
http://www.belltech.com/products/belltech/rear-lowering-components/shackle-hanger-kit-16.html
The instructions make no mention clearance issues. (obviously)