I can attest to parts availability problems for the dana 27. Used stuff is out there but GOOD used stuff is getting harder to find. Struggled a bit to find the right new axle shaft u joints as well. Should have been a simple part. With the help members here, we found some listed for a different application. I've resisted the Dana 30 option for many years. I now realize the reality of the situation and, with the exception of an accurate restoration jeep, I'll use a 30 on any future project.