https://www.youtube.com/watch?v=jdW1t8r8qYc&index=2&list=WL (https://www.youtube.com/watch?v=jdW1t8r8qYc&index=2&list=WL)
Fantastic video - you can really graphically see why the sidevalve is no longer popular - look how the flame has to move around to get out of the cylinder...
That head looked like regular perspex, I'm surprised it stood up to the full throttle treatment...