Comment by gooseyard

Kevin Cameron from Cycle World has written some of the most fantastic articles about these topics, in particular there's one that I'm struggling to find about the problems with solid camshaft mass when rpms started to get really high and resulted in cam oscillation and failure, so they were made hollow, only to then discover they got too hot, which led to making the sodium filled, and on and on.

Also a couple of great ones about the struggle to find alloys for radial engine cylinders that could flex without cracking. His writing is so insightful and concise!