2.66 low gear vs close ratio

There is no matching for you. You already have 400cubes, and a reasonably lightweight pick-up.You already know the splits suck. The splits will suck no matter what rear gears you put back there and no matter what tune you put into that 400. And to sink a ton of cash into a GV to be used as a splitter,is, as I have detailed,mostly a PITA.
And the O/D 833 will be very nearly the same.
My friend, you need a pass-car non-o/d 4 speed or an automajic.
I have an 84 D100 with a 4bbl-teener, and a 2200stall 904 and 3.55s,and a traction aider, makes it a pleasure to "flick" around. Well "flick" is stretching it, but she slides pretty good with 275/50s. With that really long wheelbase it's really easy to control.

IMHO a 727 with a stockish TC and 3.55s would be a real pleasure. For $500 to $700 you could be giggling like a little girl in Daddy's arms. I'd even try it with 3.23s.
Sure would beat the hate you're feeling now....