Interesting you should respond owning a '90 also with a 700R4 & a 3.42!
Rest of the story; My Black '75, 6 cyl.,, 3 speed, 3.42 is going to end up gutted of all running gear and just so happens my friend who owns a '90/700R4 needs a rear end. So looks like he's the lucky guy! We didn't have a clue as to how well the rear would work, thanks to the response's now we know.
I will be replacing my running gear with a SBC, 700R4 & a narrowed 9" Ford.
I do have an extra complete 3.42 rear end complete with G10 springs, etc. if anybody needs one!