jrthone,
I think you're missing the point, .. more flow doesn't mean more power, ..
it's just not that simple.
If it was we could just put a 2.8" valve in a 600cc port and flow 1000 cfm, ..
but we both know that wouldn't work.
We have to consider air speed BEFORE the mass airflow volume or CFM.
If you don't have proper airspeeds you will never fill the cylinder over 100%
that is necessary to make the power levels we are discussing.
Exit speed of the intake charge out of the valve and into the chamber is one of
THE most important design issues to making good power.
Slow, sluggish air speed and power drops off fast.
So, .. this being said there is actually a fine balance between the mass flow or
CFM of a head designed for an application, .. and the airspeed or velocity that
head is designed to produce.
Big holes make big cfm numbers that look good in magazine ads but don't
run well on the race track. So that being said, yes I could likely make a -3 flow
another 39cfm, .. and it likely wouldn't run worth a crap on a typical bracket engine.
Case in point, .. I know of a head that was advertised at over 500 cfm, ..
and actually did it on a good bench, .. and makes less power then my standard
RFD / Victor or an out of the box -3, .. by a bunch.
David, .. I love the 1803 big duke, .. damn nice head.
Curtis