please give a little more discription of what you are talking about

If I read correctly you swapped a wider rear axle from an 86 into your 85
and the pattern doesn't line up on the new flange

what third is in the new housing v6 or 4cyl third?
you could just swap your old third into the new housing.
but if the new third is a v6 third you would want to keep that instead of the 4 cyl third
just for kicks is your 85 a turbo? if it is it had a v6 third

that was all just to clear things up about what you were trying to communicate
the simple answer is to just redrill the flange like mentioned above.
I run double drilled flanges on my junk.
I broke a rear ring gear in my 84 and found a third from an 79 that had a different flange pattern.
So I just rotated it 45degrees and redrilled it. easy enough. now my 79/84 flange will fit either or.

I was going to swap yokes on the shaft but the above was easier.