I have a 79 k-5, 4-inch lift with 33's, I put a 2-degree shim on the new re-arched springs and I am still having problems with u-joints. I get a loby vibration when I take off from a stop and the u-joints have in the past been eatting up needle bearings. I put the napa heavy duty u-joints in and they do the same. I have the original drive train still in it, 350/350/np203, so I am asking since there are a lot of you out there with lifts, what do you do about this? Which u-joint do you recommend? I was told by someone that I should put traction bars on the rearend to stop the vibration on take offs, would that help? I just need info on this since I am driving the blazer everyday. Thanks for any help you might have.