8 1/4 sure grip 27 spline

I saw in another thread that when you use the Jeep Dana 35 stuff that you have to use the ring gear pinion and carrier altogether. I already have a new set of motive 373 gears for the dodge 8 1/4
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How would you change gear ratios on one of those axles if you have to keep the ring and pinion with the carrier all together? I can't see that they would match the carrier to a ring and pinion specifically.