www.diy4x.com for a shackle in the rear and B52 swap up front. You end up with 4" of lift, a smooth ride and a good amount of off road flex.
www.vaporworx.com for the fuel system. You can swap in a later model 88-91 Suburban fuel tank under the bed and weld in a fuel pump mounting kit from Vaporworx to use the OEM fuel pump from the donor truck.