Driveline vibration

Did you have the drive shaft made. I had a Volari years ago we put and 8 3/4 in . Had a drive shaft made and they balanced it. They did it again twice.

I found a old original drive shaft in my pile that fit and the vibration was gone. It ended up being the drive shaft u-joints were not clocked the same front to back. If they are off just a little it will vibrate.

Hold it tight on a solid straight Steel beam on its side. Make the caps equal side to side on the front and the rear should be identical. Not saying this is definitely your problem but Something to check. Its something that many overlook.