I stopped into a 4 wheel parts store to ask about leaf springs vs. coils for the back of my '70 EB. It was set up on 2.5" blocks with the original leafs on top of the blocks. The guy told me at the store I would need to get the stock 1" block to sit on the axle and then put the new better leafs ontop. Is this the best way to prevent my shudder or should I not use the 1" block for the lift. My car has a 3" lift in front and about 3.5 in back and told me the 4.5" leaf pack would work and look good as well. So second question is, any problems with lifting the back about 4.5 or 5" and the front is only 3". I think my breaklines and driveshaft should be fine?