I ran 32s on my 85 truck with the 4.10 gears and 33s pushed me to step up to 4.88s.
I think 4.56 would be great for 31s and 32s, but would go 4.88 with 33s. Maybe you could do 4.56 with 33s if you did the 10.50 or even 9.50 width if they are still available to keep some of the weight down.
I agree. I am running 4:56s with my 31s and its as good as it gets or 3rd member gear-wise. I ran 31s, 32s, and 33s with my stock 4:10s in my 85. It was OK, but I could not use 5th gear sometimes. With the MC Crawler t-case, wheeling it didn't matter. 4:88s with 33s or 35s is a good gear ratio. If you plan to run 33s, I'd go right to 4:88s.
Gnarls.
