Although not in near as good condition as yours, this is a 1954 letter I have from N.H.R.A. adviser Dick Forbes inviting the Boise Idaho Gear Jammers to participate in the Pocatello, Idaho championship drag races. It also has some very well known names in the left hand margin. Mick
I don't know about the rest of you guys, but I had to look up gymkhanas to find out what the heck it was. gym·kha·na jimˈkänə/ noun plural noun: gymkhanas a day event comprising races and other competitions between horse riders or car drivers.