This is a short film of the Belgian Grand Prix, at Spa-Francorchamps on June 18th 1961. Frankly, the editing is a bit of a mess, not being sequential or chronologically set up. The GREAT part about it though is that it’s in 60 FPS. That being so, you can really appreciate the details, specially on the onboard parts. As a comparison, you can see here “regular footage” of that race.
According to legend, it was footage like this that inspired John Frankenheimer to make one of the most famous racing films of all times, “Grand Prix” of 1966 (you can watch the whole film from that link).