Thinking about port and polishing my heads on my silverado to get the full flow of air through my engine wondering if this is a good idea ive heard of diffrent ways of doing this like taking a sharpie to the gasket and outlining the edge of the holes, and grinding the gasket to the size of the heads holes is this a good idea??? also wondering could i lose preassure in the air flow in doing this? any ideas will help thx