Bob
I wouldn't worry too much about cams and ports. A bump in CR would help you out a whole bunch on Methanol. These engines don't need ports and cams like you had in the Honda. Check out the cam specs on a 600 Yamaha>>>>not very exciting when you compare them with the old Honda. Since the Midwest Bunch is pretty open this year you can do pretty much anything you want to.
When thinking about these engines you have to forget all of your 2 valve ideas. I got a stock Ford Duratec 3.0 head and it flowed about 75% of the old style Esslinger head and took care of a 25% smaller bore.
I would probably go with as big of a piston as I could get with as much compression as I could get. Good rod bolts and a little stiffer valve springs do a good valve job on it lighten the stock valves and go racing.
Honest Dad himself
