I agree OZ. Edelbrock has a very good combustion chamber design that does induce swirl and unschrouds the valves. Rest of the porting etc is not anything to write home about, but that's just my opinion.
http://www.sacoriver.net/~red/harley.html
Check the bottom of the page, right
http://www.sacoriver.net/~red/harley.html
Check the bottom of the page, right