The early Camaro and Nova share the same trans crossmember. The 350 turbo/stick cars used a rectangular pressed metal crossmember. The 400 turbo cars use a round, tube type, with quite a big rearward loop in it. A Monte or Chevelle 400 yoke will work with most 400's. Check to see if there is a vent hole in the yoke end. A big O-ring on the tailshaft.
I get my d-shafts from a pile at the yard. The last one was actually a Ford, but it fit perfectly.