FWIW & IMHO:
I don't believe that there is one, and I don't ever remember seeing anything about one, but there is one up in northern Kalifornia that I occasionally see members post from as fas away as central Kalifornia. You might want to try a site called: www.SoCalCarCulture.com
They have msot of teh clubs listed fron everywhere in Kalifornia, I think even central & northern Kalifornia.
HTH
FWIW & IMHO:
There is a Buick club somewhere in Nor Cal that might have enough members in Central Cal to make it worthwhile to join.
"Northern California Buick Club" maybe.
It's Northern California but check it out. Fairly new. We have about 7 GN's, T-types, Several Syclones and a Typhoon. Still updating the site with members pictures and etc...
We are meeting currently at Mountain Mikes pizza on Sunrise and Antelope in Citrus Heights. There is a map on the rcspoolers web site. Come check it out. Love to have you.