Meritor Mx-14-120 front axle gearing swap?

I can only find a parts breakdown from Meritor that is not including the center.... and found gearing OPTIONS on the Cummins website for MX-14-120 with 4.30 option as lowest ratio. Am wondering what center can fit in this lineup of axle, as in take it out of a rear axle to put into the front???? I have a 2004 4300 that will be getting converted to having 4x4. Found a lot of axles nearby, all from 2017+ 7300 and 7400 Internationals. Am having a hard time finding info on this. I am unsure of what rear axle I have in the truck, has no ID plate on it at all, just Eaton stamped in the casting. I believe the ratio is 4.30. I am getting ~approx 4.xx driveshaft turns to wheel turn. Truck runs 75 mph with 6+1 2750 rpm, 11r22.5 rubber.

Any info is appreciated! Thank you!