I can vouch there is already a porting head program for the sidewinders. Larry Smith
has ported, flowed, sawed apart, and done rigorous test on these heads for Todd Marsh,
of Marsh Performance. I have bought and used several myself, and have so far been pleased. As an engine builder I see them as a great and affordable entry level head, with
Definite room for improvement with a professional port job like Larrys or others out there
grinding. Larry ports in house at my shop,(HP Engines). You can pm or call shop or Marsh
Performance for more specifics or to contact Larry. Hope this helps.