Easily, just with a properly blended valve job.
I actually did some H-d heads last summer. The dude came back after riding for a while I guess he was impressed, I can't say what the improvement was because I didn't put them on the flow bench but just by using some basic flow knowledge (which I have a little) I guess it made him happy
I know one of the machinists that built this engine originally said he ground on those things for days! Lol before I had him redo the valve guides I took a few pictures things look like they're pretty hogged out already
