There are various stages of porting done to the heads, each concentrating on a specific area of the head (ie bowl, combustion chamber, intake and exhaust ports, etc). The labor costs involved can range from a few hundred dollars to well over a 1000 bucks (per head). I am currently finishing up the bowl porting on my TFS Twisted Wedge which basically involves smoothing out the area beneath the valve (and valve seat). No real reshaping is going on, rather a smoothing using an 80 grit roll on a long shank. This helps speed up the fuel flow and adds around 20 - 25 horsepower. Gasket matching (intake and exhaust ports) has shown not to aid very much in the horsepower department. Based on your cam/valvetrain and the application (street or strip) will determine the amount/extent your heads need reworking. Be very careful though, as more is not necessarily better, especially on the street. My shortblock for my 65 X-tremestang is based on a 1995 Lightning 351W shortblock assembly that has receive a full blueprint and balance from Mark Jeffrey at Coast High Performance in Torrance, CA. My displacement has been left stock and I am using a TFS roller cam 542/563 with Harland Sharp roller rockers. My car is being built for the Nevada Silver State Classic Challenge wherein you are allowed to run top speed over a 90 mile stretch of a public highway in the state of Nevada. To view progress of my car, go to
www.bossman-motorsports.com and click on CURRENT PROJECTS. If you need more info on Coast High Performance, email me or check out any of the popular Mustang mags as they advertise in quite a few.