i have heard it mentioned here various times, and seen it in peoples mod descriptions, but what exactly is involved and what are the results?

thanks

 

Try this as a starter http://www.mazdatrix.com/faq/porting.htm

 

Street-porting is a way of getting more HP out of our engines by enlarging and reshaping the intake and exhaust ports. By doing this it allows our engines to draw in more air, and get rid of exhaust quicker. Porting also changes the duration of the intake and exhaust cycles. Street-porting is the most common port done to our cars because it isn't too drastic and it allows our cars to still be streetable. Some ports such as monster ports, and peripheral ports will make your idle horrible(and above 3-4k) and make your powerband only useful above 8000rpms.