The first video is of the Arrows F-1 car and it is indeed a Cosworth engine.
It's a 3 Ltr. V-10 that reved to about 18K RPM and made 850ish HP.
The engine that followed when the rules change was inacted was basically the same minus two cylinders.
In V-8 form, we revved the engine to 21K RPM during qualifying (in the Williams car). In 2006 the Cosworth V-8 engine was thought to be amongst the best on the grid (we just didn't have a good car to put it in).
The engines (both V-10 and V-8) actually use a pretty large bore diameter. They're just under 4 inches.
With a displacement of 2.4 ltrs you do the math
on the stroke
(I don't want to have to kill you).
P.S. Ours idled between 2500 and 3000 RPM...