Joe Ortiz, the curator of the L.A. Fire Dept. Museum, has his own business in which he provides vintage fire trucks, police cars and ambulances to the movie studios in Southern California, and also sells a few vintage beacons, Mars lights and sirens (mostly B&M or CAM) here and there. He has a huge compound in one of the bedroom communities near Burbank that I've seen, and the number of firetrucks, ambulances, rescues, etc. would make you faint.
Joe is a member of Professional Cars International (PCI), which puts on a Summer Meet that sometimes begins at Joe's compound (which is in Shadow Hills, I just remembered). From the starting point, all the firetrucks, ambulances, rescues, etc. that participate take off in a Code 3 Run (all vehicles entered must have working lights and sirens) which winds it way along the freeways to an area known as Hansen Dam where the remainder of the meet, along with the American Heroes Airshow continues. Quite an event.
Lou Farah, PCI president, among other vehicles has a very nice 1969 hightop Stoner/Chevy Suburban ambulance. When I went to their meet in 2002 Lou allowed me to drive the Suburban in the Code 3 Run. That's an experience I'll never forget!