I just got a set of 3-leaf multi-leafs to replace my rear mono's on my '67 bird. Already have the bushings, and axle pads. Conversion kits seem to have a new set of U-bolts and a steel spacer. Do I need new U-bolts? Seems like mine have a little extra...Where does the metal spacer go? Do I really need to buy one of these kits? They all run around $90 from what I can tell. Year One's have a fat metal spacer while Detroit Speed has these thin aluminum ones, that are shaped pretty differently. What gives? Any suggestions?