For most 911 machine shop work: German Precision in Sunnyvale; it's run by Ted Robinson. Very good competent guy. Call him at 408/747-0728; leave a message he'll get back to you.
For cam work (repair, regrinding and modifications): D. Elgin Cams in Redwood City at 650/364-2187. They have a website:
www.elgincams.com
Cheers, Jim