Before Laguna Seca, there was the Pebble Beach Road Races, 1950-1956. Very interesting documentary (2016) on the beginnings of the SCCA and road racing in America. Several 550 Speedsters and a couple of 356's were run in the later years.
I found/watched it via Amazon Prime.
https://www.amazon.com/gp/video/detail/B0756JZTF4/ref=pd_cbs_318_13