BAD vibration TKO600

[chpr1972]

I put this in wrong place. I have a vibration at 60 mph in 5th gear, at about 1800/1900 RPM in seat of the pants. Below that, there is no vibration. I normally drive around town under 60 mph. The other night I needed to change lanes, so I stepped down on it to about 70 mph. It vibrated so hard that I thought rear end might come outta the car. I pulled the rear tires and vibration is still there. There is no vibration in motor to 4000 rpm. With the drive shaft out, it is hard to tell if there is a vibration in the transmission. U joints check good, free and no play. Since the rear end [Ford 9" 370 gears with clutch pack] was leaking, I pulled it and had a guy at 4x4 garage look at it and found nothing wrong. There is 12,000 miles on the car. I recently had to put new cam/ rod/ main bearings cause rear cam bushing was installed wrong. A new clutch disc was installed also. !966 Lemans with factory setup Hotchkis 1" dropped springs with lift bags. The upper arms are adjustable. I have reset it 3/4 times at least. Last time I used speedways formula and .5 is where it is at and within point 5 is good. I also used Tremec phone app. It checked good, all green 01.3/00.6/00.7