[V8] 5 Spd axle interchange

[J123fs at aol.com]

Hi folks,
Car has a split inner boot on my 91 5psd.
After rebuilding them last time I'm strongly considering buying a rebuilt  
unit or two swapping them, and then building the old ones at my leisure for  
future install as it would be nice to have spares...
Here's the issue: No complete assembly's are available for the five speed  
:-(
Answer I'm looking for what other manual trans driveshafts interchange with 
 the 5 spd? 200 20vt? UrS4 or other C4 manual trans axle??
TIA!
Jack