[lolife99]

89-81 suburbans are the same as the 73-87 burbs.
Also mentioned you should have the 1.25” rotors.

I had a 91 burb lowered with 4” drop leaf springs.
You will need to shim the carrier bearing mount to help with driveshaft length.
I had drop spindles and springs up front.

I see a lot of people using flip kits on the rear.
TinWorks Fabrication make a bolt in c-notch with the “suburban only” body mount built in.
This gets you axle clearance, but also gets the center section of the rearend close to the bed floor.
Good luck with your build.