Ive just read some technical info relating to valves, relevant to Cam choices I think so i thought i'd post it.......

It says:

the most efficient airflow through any valve occurs when it has been lifted 25% of its diameter.
For example: a 38mm (1.5") valve will require a lift of no more than 9.5mm (0.375")

Further opening of the valve will result in minimal increase in flow.

So....Anybody know the size of a standard Cossie Valve???