I have been doing some initial research into this subject (mainly whether or not I can pull it off myself), and on another forum, there are tons of search hits, but all the posters are English language retarded. I like this forum, because for the most part, people here can form sentences and spell correctly. So, my question is, does "porting and polishing" really provide a performance increase, and is it a DIY type job? Otherwise, it seems as if custom equipment must be purchased, and at a high price, no less.

 

OK, a friend of mine found a car mod FAQ online, and this is what the author says about this subject:

"Porting is a simple way of gaining HP by grinding out some of the intake/exhaust ports in a head and/or intake manifold. There are special tools that help do this and it’s not a 'do it yourself' job unless you know how much to grind without worrying about the heads and/or intake breaking. Polishing, however, can be done yourself with a dremel power tool. Polishing is simply polishing up ports to a nice high shine. This promotes more airflow and allows the air to flow easier. The point of porting and polishing is to allow for the heads to breathe more and thus allowing for more HP; however, porting a head too much can result in a loss of torque as the engine cannot deliver enough velocity alone to 'push' the air into the engine. Expect to pay quite a bit for a port and polish by a reputable engine builder when it comes to heads. This is a mod that should really only be done if you’re finished with bolt-ons and need that extra HP or when you have an extra set of heads lying around."

Author: Dennis McCarthy

Therefore, is just "polishing" the ports an effective improvement?

 

I know the other forum you are talking about. Too much Smackdown responses on that forum.
As far as porting and polishing, it is something I have done myself on several projects. Porting is making the passages larger, polishing is making surface smooth. I typically use a dremel or air grinder with grinding/sanding wheels as needed.
If you get a good set of aluminum high flow heads no need to port, they considered that in the sizing of valves. Most porting is done to stock heads when you are also adding larger valves. What is important for all heads is gasket matching the ports and polishing.
When talking about porting and polishing of intakes, many people will have different opinions on value of rough texture in the intake for air fuel mixing. I typically will gasket match ports and only remove obvious casting flaw roughness.

 

About how much should it cost to get done? By a reputable mechanic of course.

 

depends on the car. 4.6L SOHC cars are usually 650-900 depending on the shop. 4.6L DOHC heads are quite a bit more due to more work having to go into them.

 

yeah it can be done at home. the only bad thing is you screw up you are out of money. and it could cost you power. if you can afford it, i would go ahead and pay for a professional to do it. JMO, alot of people do it themselves and it works fine. i just couldnt see butchering a set of heads myself. maybe goto the junk yard and buy a set to practice on

 

ya your looking at 15-40 hp mostlikely 15-30 but i wouldnt call it a diy by any means

 

ive ported plenty of intakes and a couple sets of stock E7 heads, but my TFS heads were done by Fox Lake. Stage II will cost ou about 500-700 bucks. when it comes to OH cam heads you're looking at a litttle bit more cash.