While we have this ancient thread bumped...
The head cross sections are awesome to study and compare. I missed this one way back in '03.
I would like to mention something to correct a misconception for anyone else reading this thread in the future. Maybe I'm being pedantic, but the O.P. completely neglected including (subtracting) the diameter of the valve stem from the valve seat throat. The effective diameter ends up being around 1.391" versus the 1.525" mentioned, assuming a 5/16" stem. So, it's not a huge mismatch between intake port and seat at all. Sixteen thousandths, not fifteen hundredths. That number is an over simplification, but a decent ballpark.
Back to our regular scheduled programming...