Valve polishing?

the gain with polishing or porting will be nill in any case with a stock cam. The gain with the headers mostly the same, what you will gain is some rpm , but loss in low end tork. especially if you go with large pipeing , stay with 2" to 21/4 . If you go with a cam so the engine can breathe then the headers will add more and the electronic ign will allow ignition to red line. It's all a ballance one depends on the other .:classic: