CPP Trac Bar: Shim Neccesary for blocked truck?

[j1970GMC]

Hi Everyone,

Im almost finished installing my CPP trac bar on my 67 C10. My truck is dropped in the back with blocks and already has a shim. Is it really necessary to use the provided shim for the left trac bar? It's starting to have too many layers....How much difference would it make to not use it? Thanks for any help.

Here is the link to the sway bar kit:

http://www.classicperform.com/Store/...ck/CP32021.htm