Cam experts:What effect does grinding a cam
The exhaust will close sooner and usually closer to TDC,
and the intake will open sooner.
This normally picks up lower RPM power, and in some cases is a better match to the engine combination depending on where in the rotation that you are getting your maximum piston speed.
If the maximum intake valve opening correlates to the max piston speed, then you can get better cylinder filling overall... not just at a lower RPM.
With a very long intake duration period, it sometimes becomes very advantageous to advance the camshaft to bring these events closer inline to match the desired power band of the engine.
If an engine is set up with long rods for extended dwell, then that allows you to run a less advanced camshaft in order to make more upper RPM power.
It's all about matching the valve events to the position & speed of the piston.



