I found your Dana Sullenger Family Tree which shortened my search. The next time you post a query, please mention your family tree.
After looking at the information and noticing that Jack was eight years younger than Margaret, I'd say they married in Los Angeles County.
You have two ways to pursue this search. You can wait until the 1940 U. S. Census for California is indexed. The 1940 U. S. Census has been released to the public but we don't know when California will be indexed.
You can contact the Kern County Assessor Recorder's office, http://assessor.co.kern.ca.us/recorder/BMD_certificate.php
and fill out the form for Jack's marriage certificate. I chose Kern Co. because of your info that he lived there from 1935-1993.
I'd use Jack's name because of the possible miss-spelling of Mihelich. Successful Searching!
Another place to search is in Lake Isabella, Kern Co.The search in Los Angeles Co. is based on conjecture at this time.
Lake Isabella is located in Kern Co., CA. There's another place I looked up Lake Isabella in RootsWeb Home page but no county information appeared.