3" is the maximum suspension lift for a 1st Gen before going to a solid axle in the front.
It is achieved by new upper control arms and new torsion bars in the front. The rear is leafs so however you want to get to 3". Shackles, new leaf packs, AAL, a combination of all of the above.
From there you can go to a 2" body lift and comfortably fit 33x12.50s