As for racing in the old Eastern Bloc, as a youngster I used to regualrly read Motoring News from UK - a weekly English newspaper that covered everything from F1 to hillclimbs on Guernsey. Arrived in NZ by slow ship about 3 months after print date but was about the only way to stay in touch with motor racing in our one tv channel, no internet world (at least until we had some good local racing journals). Anyway, in the UK off season they would always do season summaries of all the classes, and delve into motor racing around the world. One of the quirks would be a review of racing in the Eastern bloc. I recall the Baltic states, Latvia Estonia etc had a mini industry of enthusiasts building and racing single-seaters without the infrastructure available in the west. Somewhat like early days in NZ I guess where the cars were created locally as best they could.
I also recall there was also a track in what was then Czechoslovakia (Brno) which some of the Euro series would visit, Euro Touring Cars and World Champ bikes. Apparently hairy like old Spa, about 18km on on public roads (see pic). Suspect there was some interesting cross-border trade going on with those events
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