I guess when you are talking like ARP you mean 12 point heads in high grade?
In any case here are a few places you might try:
(Anaheim) Mcfadden Dale Hardware
http://hstrial-mcfaddendalei.homestead.com/
(Anaheim) Shamrock Supply
http://www.shamrocksupply.com/
or you might try
http://www.mcmaster.com/# , they are in Santa Fe Springs which is pretty close to O.C.
Pacific Coast Bolt also is in Santa Fe Springs
http://www.pacificcoastbolt.com/site/index.html
they are more heavy industrial though.