Well, here we are, 10/1 and I'm finally running
.
Had the the car apart and back together in various stages don't know how many times since I started this thread. Three things came to light:
1. The transmission needed a rebuild which was tackled first, shaft wear and bearing issues to be expected in 50 year old parts. Shout out to GJCAT427 for doing the wrenching for me after I collected the parts from DKT and messed with other stuff.
2. The driveline was not correctly set up relative to parallelism of the tailshaft to pinion flange. Thanks to Drew P for sending up his angle finder, saved me $100 for a tool I'd probably rarely if ever use again.
3. The biggest issue discovered beyond the above was that my new driveshaft was not cutting it. After the above repairs the vibration remained to a lesser degree but still way too much to ignore.
Enter a new driveshaft from CCI driveline in Michigan reputed to be good to 7,000 rpm. Don't mind sayin' I was holding my breath while running it up through the gears, but that new driveshaft finished the job.
Smooth as silk
. Well, 50 year old silk anyway, got lots left to do.