Help me figure out what I have on the truck?

Hey guys I just bought the truck it's a 04 6.0 2wd and I'm having a hard time figuring out what is done to it suspension wise. On the front it has a 1 1/2" spacer under the spring. On the rear it has 1 1/2" block with air bags installed also. The truck sits higher on rear about 2" more then the front and that's with all the air out of the air bags. I'm thinking about putting a 2 1/2" spacer from maxx lift and going with 20x12 with 33s. Currently has 285/70r17 which equals to 33s and they look small.. since it's a 2wd is it barely how a 4x4 sits stock?