Well, there's Big D Mustang in San Leandro (next town north of Hayward). Then there's Mustang Magic in Fremont (two towns south of Hayward). If you like street rods and muscle cars there's Kassabian Motors in Dublin (just east out 580 from Hayward) as well as the Mustang Parts House. And there's Specialty Motors and Car Scene in Pleasanton, just across 580 from Dublin.
Theres a little whole in the wall shop in between Your Hayward and Halfmoon Bay its in BelmonT Calif on El Camino just a little below Ralston Ave I believe. Small place he has some neet stuff and nice guy, I can't remember name of it but he only keeps hours between Tuesday and Friday I think Iam sure you can find out info if you stop and check yellow pages in Belmont, only gonna take maybe 10 minutes out of your way.