There are 4 Dana 30 axles that I am aware of.
1) The CJ/Bronco/IH Scout II long pinion std cut version
2) XJ/YJ short pinion reverse cut (high pinion)
3) TJ short pinion std cut
4) JK dana 30 (not really familiar with this)
Only #1 above was used on a CJ from the factory. All the pinion shafts for these will be exactly the same length. You say you need assistance but you don't say what you need assistance with.
XJ TJ CJ PINION Diameter @ inner bearing 1.376"
XJ CJ PINION Diameter @ outer bearing 1.125" ; 26 Spline
std cut CJ Dana 30 Pinion length 8 9/16":
CJ,XJ-95 Outer Pinion Bearing: (same D44): (Set50) Timken 02872 ; Race 02820
CJ,XJ,TJ Inner Pinion Bearing (Same Isuzu D44): Timken HM88649 ; Race Timken HM88610