Something I tried with the Harley style oval port was an experiment to see just what a change to that shape port would do in an A65 BSA head using the same 30mm entry and std inlet valve size. I checked the flow on a std head from 67-69 era and also on a '71 as the porting is a bit different. The '71 flowed 111CFM @ 28"W the earlier head 109CFM bare without carb or bell on the port, both about 60cc port volume. More than stock lift wasn't making a difference.
Between the 30mm round entry and the valve I lifted the port floor and port roof and widened it turning the port smoothly down onto the back of the valve. Port volume still measures 60cc but the flow surprisingly is now 135CFM, if I put a little radius at the port entry 142CFM. I think this is pretty significant and would make the world of difference to a stock A65 and let it make extra power and pull higher RPM without any losses of power down low. It's pretty simple to do and doesn't go near breaking through anywhere, but requires the port floor to be filled and lifted.
84cc port next to the 60cc port. 197CFM and 135CFM I should take a mould of a standard port for comparison.