Today I went to a rubber dealer and aquired some rubber discs which I plan
to place under the 3/8 inch thick shims I made for my left rear springs.

I have extra rubber shims if anyone is planning on similar improvments to
your springs. For $1 each the rubber discs are available [plus actual
shipping and packaging $3?]. (You'll have to make your own Teflon shims as I
did. A cutting board costs around $10 and is good for about 4  to 6 shims.)
You can see them on my temporary web page at:
http://members.home.net/holisticdream/temporary.htm I'll be putting them up
on ebay soon so that they can be available to someone rather than gather
dust in my storage area.

I have several 6 inch diameter rubber discs about 1/16 inch thick and
several larger 1/8 inch thick rubber discs from which I had to cut down to a
6 inch diameter piece. And also cut a 2 inch hole in the center for the rear
springs. (When I do the front springs they will require a 3 & 1/2 inch hole
and 5 & 3/8 inch diameter disc cut.)

The top photo on my temporary web page shows the white teflon cutting board
shim with the thinner rubber discs on either side. The uncut stock is below.
The larger one is 1/8 inch thick disc and the smaller diameter is the 1/16
inch disc.

However, before you buy these and spend money on postage check with your
local rubber dealer. You may be able to find a better deal or at least save
on postage and packaging.