OK Bell tech 6419 4" shackle & Hanger kit arrived today.
included is the following: 4 new U-Bolts. 2 new red urethane bump stops. 2 forward hangers. 2 new rear shackles (very different from the 6400 2" shackles). All the hardware (grade 8). & (GASP) 2 pinion angle shims.
Get this: NO INSTRUCTIONS at all... except for the "carrier bearing realignment plate install" for a new GM truck
So... I am headed to Bell Tech's website to find instructions...