I have a 3.8 in mine with the r150 f and adapter plate so far so good.
I had a g52 at first, but broke it, then rebuilt it and broke it again.
Then I got a cheap one from an 86w56 broke that one
Then got another w56 and broke that one as well.
Then I got tired of wasting money and went to the r150f set up
and did that just for replaceability if I break it again
since the r151fs are so hard to come by now days.

I also had my 21 spline case converted to 23 spline as well since I'm running dual cases.
I figure with dual cases and 4:56 gearing I'll be ok with 35"-37" tires.