1968 with T56 and Ford 9" Vibration

[Trsmotrhed]

My 68 I picked up the other day has a vibration at 65 mph and above. I knew that on the test drive and discussed with owner.

The PO told me he installed a T56 and a Ford 9" all at once and ended up with the vibration.

He left the low tranny hump and angled the tranny down to clear it. Looking at pics online, this needs the high hump and some lovin to make the T56 fit.

I'm thinking he got the driveline angles all messed up. He has the back of tranny down 6 degrees. The 9" rear end is up 5 degrees. I'm thinking he has way to much down angle on tranny and tried to fix it angling the rear end up causing the vibration.

I broke my hip a couple weeks ago so I can't really crawl around under the truck very good right now. I'm thinking this is a great place to look when I can.

I've been reading driveline angles until my eyes hurt. Lol. I've done several engine, tranny and rear ends on trucks and never had any issues following the tranny down 2 to 3 degrees and match the rear to that.
Think I'm headed in the right direction? Thoughts?

Driving me crazy not being able to work on it. Thanks.