Unfortunately in 1949 a crash occurred during the Cleveland races resulting in a P-51 Mustang racer crashing into a house near the course. The pilot and 2 occupants of the house died as result of the crash (a mother and child were in the house). Following this incident the races were suspended from 1950 to 1963. This hiatus and incident must have meant Cleveland lost their hold on the race as upon resumption in 1964 the race was held in Reno, Nevada. The 1949 race looks like it was an incredible event with an amazing array of aircraft participating in the races and it is a shame it had to end in that way (take a look at this link for a great summary of the race, the aircraft and the events that transpired throughout the day).