what is exactly done when the heads are "ported"? what are the reasons behind so much performance increase? just wanted some FYI. and i know shoebox will see this so shoebox, u should take ur engine apart so we can see a bottom end rebuild

 

Look inside the intake port on the head. The air has to go in the port, over a "hump," then to get out it goes into the port, over another hump on the opposite side, then out the head.

What they do is shave down the hump on the inside, resulting in better head flow. Also match the intake to the heads. That will help a little, but the main thing is getting that hump in the heads milled down. It's like a car flying down a road.... Going up that hill will slow it down. Mill it down, and it makes it a little easier to roll through

 

if you are serious about wanting to see a bottom end rebuild, then click on the following link: http://www.walmart.com/catalog/produ...uct_id=1955114. this book covers a bottom end rebuild on an lt1/lt4 engine and is only $12. i picked it up (at the recommendation of shoebox) and it pretty much answered most questions that i had or would have had concerning a rebuild with our blocks. its very informative and worth checking out.
dave

 

Ok basically when you port a head you're modifying the port layout to a degree. On mass production factory heads there is a lot of potential left on the table. On most cars the ports are FAR from optimized from the factory. Once you go into the heads you're looking to do some basic things... increase air flow, create consistency in flow between the runners, and shape the combustion chamber accordingly.
All port work direction will be dictated by the engine application. Generally all set ups will gain power from a basic "clean up" of the runners, a good valve job, and port matching with the intake. This will really pick up the low & mid range flow on the head and give you some great street/strip performance. When you start getting into the all out big cam stuff things change. For this stuff I really don't worry about the low lift #s on the intake side, but concentrate efforts on making gains in the mid & upper lift #s. On the exhaust side I do the opposite... in my book low & mid lift is king here.
In the overall process of working heads the last place you want to cut corners is the valve job. Too many folks over look the valve job. I can guarantee that a bad valve job will kill power much quicker than anything else on a head.
Well there's a little bit on heads for ya... hope it helps some.
Steve...

 

i am definitly running to get that book, if one is to port the heads does he need any after market parts? like valves etc? or is he just shaving things off the stock sockets? cause i see people on here porting their own heads and i work for the marine corps and we have a motor T shop here with everytool imaginable and i was talking to the ssgt there and he said that if i wanted to use it at no charge (auto body shop charges) then i could. just wondering cause i plan on taking the engine out to do my cam and some other things that would be easier with the engine out.