Is there info in the archives, or another site that would provide diagrams or photos of what is done to the ports to improve breathing?

    I am rebuilding my 20B as a normally aspirated engine to install in the RV-10 I am building, and the 240 HP from stock is a little less than I would like.  Any input would be greatly appreciated.

Phil in Willowbrook, RV-10 #40220

I think 240 HP is a bit pessimistic.  Check my dyno results on N.A. 20B at http://members.cox.net/alg3/Dynamometer%20test%20report.htm

Stock porting, just some polishing. 

Al