Lee Ackerman came up with this little tidbit while doing some research;
In 1948 IMCA ran 138 races and had 9 more on the schedule that for some reason (like rain) didn't happen. They started on February 3rd and finished on November 28th both in Tampa. Some days they ran two events on the same day. On May 30th they ran 4 races on the same day at 4 different race tracks in 3 different states.