Quote: I have heard that certain heads with very good flowing exhaust ports (compared to exhaust) can over-scavenge the cylinder and actually suck a lot of the intake charge into the header, where it continues to burn and overheat the pipes. With some of the intake charge lost, power would be down.
Perhaps over-camming the exhaust would do the same.
Absolutely. Even if the engine doesn't suffer a hit in the power department, it impacts fuel efficiency.
