Bob,
I know that Otto's was a top 914/911/912 aircooled shop when John was there/owner, but have heard since he passed in 2013 that it has apparently gone to primarily new Porsches.
Otherwise, I don't know about Westside anymore, but if no one else chimes in, down in OC there are: Bill Brewster in San Clemente, AASE in Fullerton, & also Der Buggy in Garden Grove knows the T-IV engines as well & does work on some 914s I know.
BTW - Bill's shop is now going by Brewster Industries:
http://brewsterporsche.com/If your 914 is running, on Sunday 4/30 8 am - 2+/- pm, bring yours up to College of the Canyons in Santa Clarita (near/before Tragic Mountain) for the Cal Inland Region's PCA Zone 8 Concours, as there should be some Teeners there who may know of other shops. IIRC the Display only is free, but even the entry isn't too bad, or just come up to visit in any car!
I'll be there judging, but with my blue 88 Westy & it's awning serving as the refreshments & reg./scoring booth - so look me up & say "Hi".
Good Luck!
Tom
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