just out on 4" superlift springs on my cj7. i noticed the shims had the big end pointing towards the front of the vehicle, i thought it might point the pinion too far up. at ride height its damn near inline with the driveshaft. now i have a lot of vibration.has anyone ever flipped the shims around(small end facing front of vehicle) with better results?

Are you running a CV driveshaft? With a CV driveshaft you want the pinion in line with the driveshaft. With a standard (non-CV) driveshaft you want the pinion shaft parrallel with the output shaft on the T-case. To answer your question, you can put any angle shim any direction you want to obtain the correct pinion angle.

You may need a shim different than they provided, or no shim at all. The transfercase yoke and pinion yoke need to be the same angle. The best thing to do is cut your spring pads loose or just get new ones ($10 pair) then set your angle using a magnetic angle finder and weld em up.