Two piece driveshaft u joint angles

I put a 4" lift on my '95 F350. Now I have some U-joint vibes on initial acceleration.

I have a 7 degree angle on the center U-joint, and 0 degrees on the rear U-joint.

The lift blocks on the rear have a pretty severe up angle built into them. I think this is the problem. I have been playing with dropping the center support bearing but no luck getting rid of the vibes.

What kind of angles should I be shooting for, and how can I correct the rear end angle? I don't see how wedge type shims would work on a 1 ton truck.

Thanks,

Sorry Boss, I used to have a site saved on my old fried computer that had some good examples of truck U-joint operating angles. But now I can't find the site/remember the name of the site.

If I find it I will post it.

did you take your driveshaft apart when installing the lift?
is the pinion nut tight?

Well I did some researching and found that guys sometimes lower the center support bearing to work on u joint vibration. Well, I lowered the center support bearing about an inch and it helped big time.

Greg