Hopefully it was just unbalanced. If that doesn't do the trick, here is a spicer driveshaft install manual that explains DS angles for a bunch of different DS configurations.
https://www.dropbox.com/s/nmo6hi36rz...anual.pdf?dl=0

Look on page 5 for the "rules" on joint angles. These are ideal setup rules, but I tried to get them within these rules on my truck.

 

The guy said it hadn't been lol. Wow, Thanks fort worth gear and axle, I appreciate the half aśś job. Anyways, it did cure a lot of my vibration issues. Still not perfect, but definitely good enough that I feel comfortable going on now with the drop and then work on my angles after ride height is all dialed in! Spoke with JamesB chassis works and I am supposed to drop off the 10 bolt to get narrowed ad a tru trac and 4.10 gears set up its weekend. Then, drop time!

Awesome, thanks! I will read up on that.

 

The guy who is going to build the rear end for me asked me why I wasn't going with a 12 bolt over a 10 bolt. I didn't think they were that much stronger, and I don't really want to do a 14 bolt. The truck is low 5XX rwhp and all wheel drive. Anyone think the 10 bolt won't last out back after its built up?