"1310 CV series to 1310 pinion yoke series" so is this the model type i should be looking for?

Also i'm looking at the sye and it says "may require mode fork shift rail to be shortened" ok one whats that, and two is it obvious to determin if this needs to be done?

Thanks for the help.
tom


99 wrangler sport, auto. 2.5 inch lift, 31 MTR's