Oops opened mouth and inserted foot lol. Lemme rephrase that retard remark. The guy locally near me was making 500 rwhp with an na single plug head. He did the porting and polishing himself removing some of the heart shape in the chamber, upgraded the valve train and installed himself. The NA heads are fine to be used, just gotta do a little work on em. Mainly putting in the turbo valve train otherwise you'll bend a valve. Posting at 4 am or what ever that was was probably a bad idea.