Vibration.....Driveshaft?

I edited my post with the link in it. Here it is again.

I chased down a bad speed related vibration by myself and it turned out to be a pinion angle that was too nose high.

Outstanding video. I am a mech engineer and can fully understand. Looks like I have some things to check. Also, I am running Caltracs with about 1/4" play for the street, so I have to take into account my pinion movement.