Last time I paid for a port job, it was $325 (including return shipping). It was on a 661... I had the seller send it straight to Mastermind in Tennessee.
Gains depends on the saw. A good way to get an idea of gains is to find your particular saw in a build thread. See what gains they intially got and your almost guaranteed that you will get that if not better.
Let's use 2 60cc saws for example. If you send a ms361 to have it ported when it returns you will drop your jaw. If you send a 562xp to have it ported you will notice a nice difference but nothing like the differnce you get with the 361.
Woodsported.....my internet certification view.....the most misunderstood, talked about, too many opinion, used as a excuse, chest thumping, overrated two words associated with a chainsaw as the world turns word. CHEERLEADERS USE IT! People want it, people get abused by it, people love it/hate it, people are judged by it! Next question please?
The woods port is being pushed to what most are hot woods saws. The cost I'd dependant on who is doing it. I think most are in the $275 range now it seems like. The only one I paid for was $150 in 2005/2006
Woods Port: 1) A saw that has been dicked with; usually resulting in improved performance, but often times not. 2) Wanking in the woods with a modified saw. 3) See Stihl bro's post above. Saw porting has got to be the most over hyped and misunderstood nonsense out there about chainsaws. The hype has led to massively over-inflated egos by the porters and by the owners of ported saws. It has also led to a caravan of porting followers that worship the ground that porters walk on, wearing t-shirts and hats, and partaking in internet flame wars against other porters that use different porting methods. Basically the woods port is supposed to be a saw that has a mild increase in compression and some amount of muffler modification and compromised EPA limitations to improve performance. A woods port saw should run all day, day in and day out, as a work saw in the woods. This is opposed to a race saw that is flat out fully ported and which runs so hot that it can only be run for short durations.
There are also different types of woods porting, and different extremes. The two basic methods used (and argued about in endless flame wars) are termed "pop-up" and "cut squish". Both increase compression by grinding the cylinder base. This results in piston slap at TDC unless there are other modifications made. In the pop-up, the piston crown is ground down around the perimeter and in many cases the top ring is removed, and the top of the cylinder is left as is. In the cut squish, the top of the cylinder is ground down around the squish band area and the piston is left alone. Now if the cylinder base has been cut down the mechanical port timing is usually also changed. So the ports are also usually ground on the top or bottom to correct for timing. The ports are also usually widened to allow for more fuel and exhaust flow. Depending on the saw model, the muffler may or may not be opened up to allow for more better flow as well. Also carb jetting may be changed to allow for more gas in the fuel mix. Also electrical timing may be advanced by pulling the flywheel and grinding the key slot to allow it to be rotated forward (advancing the spark). Taken to extremes, these ports may extend well beyond a 'woods port' and become race ports. Also if they are not done correctly, they can result in a crappy running turd.
For me a woods port costs about 50 bones. That being the machine work on the cylinder and my time. The enjoyement I have gotten from porting the saws myself and getting to chat various "knowledged" people that know what they ar doing is invaluable.
Woods porting is a gimmick. Before long, they'll be offering them on late night infomercial's....60% gains for only 10 easy payments of $59.99.