You want an inlet cam that can get as much gas in the engine as possible and then an exhaust cam that holds it in the cylinder long enough to give good pressures so that when it evacuates the engine it aids spool up. This is where the correct port sizes are essential, as it can melt if you get it wrong. Can't tell you any more about the port sizes or I am giving away Harvey's years of dyno work .

This is why the BD 10 cam is so shit, it has the same duration as a BD16 (264°) but no lift, so it gives no low end power whatsoever, for only a very small gain at the top end.