Ken sent me a link to some cool videos from 1981 on the Cosworth DFV Formula engine. These are pretty interesting:
That piston forge you see in the beginning of this video is still in use today at Cosworth UK. I think this was when the DFV was still trying to hold off the turbos.
This video has a pretty good explanation of spring surge and valve float. It is also what can happen when a cheap ass uses a stock valve spring with a high lift cam and high RPMs. What was used to visualize the explanation? A Slinky of course. At the 3:00 mark is the late Keith Duckworth (the WORTH in COSWORTH), the grand master himself.