Damnit, it wont post my diagram right.

Let me put the idea into an RC perspective. Imagine looking down the carb opening on one of our motors to see the intake port on the crankshaft (which is a rotary valve). Instead of the normal rectangular shape you would see something more like this:

BACKPLATE
l l
l l
l l
l"-. .-"l
l . l
l l <------Hourglass shaped crank intake port
l . l
l_-" "-_l
c
r
a
n
k


The overall length of the port would be much longer than normal but you wouldn't want a port that big at full open (it would reduce the velocity of the air/fuel mix killing bottom end torque) so it narrows down as it opens and then widens out as it closes.

I like this idea, I wonder how long before someone steals it