Organizers of the first High Performance and Custom Trade Show, which was held 50 years ago at Dodger Stadium, recognized early on that the Show needed to move out of the ballpark’s halls and into a proper convention facility for it to have any growth potential. The second show—already being referred to as the SEMA Show—did just that, relocating in 1968 to the Anaheim Convention Center.
https://www.sema.org/sema-news/2017/11/growth-potential-unlimited