72 burb frt.and rear diff. interchange

[Weeg]

I recently purchased my first 3 door suburban 4x4 3/4 ton. But it has 1/2 ton diffs on it. I was wondering if anyone out there can tell me if 1986 3/4 ton diffs from a suburban would be direct replacement on my burb, or if they would have to be fabricated to fit. I also have 35'' tires on it and was wondering what gear ratio would be right, it has a 383, 400 trans, 205 transfer case. I would still like to able to drive on the highways but occasionally take it off road. Thanks for any help.