I know This maybe a a stupid question that will get a few smart *** answers.. but can this be done to a fourstroke?
How about do you do it ... could someone please explain to me down to ever last detail?
Thanks.

 

yes it can, and gain enormous power gains. Although I have never done this on a quad or single cylinder engine. Simply port and polish the entire exaust port (s), and the first 1/2" below the valve on the intake. Port match the intake and exaust to the head so they are the same diameter/dimension.

It works great on a V-8

 

Are you talking the 400ex head? I have been told by 2 national motor builders NOT to port the 400ex head unless you are wanting a high powerband. The 400ex head already out flows the carb so the gains are minimal unless you have a larger carb and numerous mods for that larger carb, then porting will help.

 

This may sound stupid but its a 300 4x4 head.

 

Yes it can be done. I had mine done at High Lifter. If you get it done make sure the place has a "flow bench" so they can do it right. If done wrong you can get a decrease in performance.