Dana 44 30 spline

I have read the 30 spline side gears can not be put in a 19 spline case (or 10 spline). I wondered why? the axle hole too small? the pocket for the side gear too small? Thinking a little machine work and they would fit yes/ no?

 

The bore for the side gear is too small. And why machine a no longer available case (19/10 spline) when new and used 30 spline cases are readily available?
You'd have to look at the case very closely but I'm betting there is not enough material to machine one out to the larger bore needed. The bearing journals on the 30 spline units are larger diameter and I'm sure other areas of the case were modified as well for the larger axle diameter.

 

Thanks, will just go with a 30 spline case.