Originally Posted by bygddy
We wernt saying they don't need to match, just that your not going to get exact, and that's OK, the OP was essentially being told that hand porting is a waste of time, and that with today's cnc machines or high dollar out of the box heads, that it was a waste of time and performance will be unimproved doing it by hand. And that's ridiculous, yes, always try and match, and don't go and just hog the the hell out of the ports, but with some time, and patience, and lots of reading and learning what works, he isn't going to hurt anything, and will improve flow, and performance. Your right, a clearly bad port that doesn't come close to flowing what the next port does is bad, but your going to get close, from experience, your going to go back to the first couple you did, and see they aren't the same as the ones you just did, and your going to work a little more, and get everything close. And they will make power.....bottom line is, just because its old fashioned or antiquated doesn't mean it won't work. If that were the case my wife would have replaced me with a 20yr old pool boy years ago.
Hopefully neither she or the pool boy is a member of the forum. LOL
Got ya yeah cnc is like stage one porting for most engines. Most high end work is hand done. Cnc is popular becasue they dont have to pay for another employee. But unless the head can rotate around the bit 360 in all directions. Its only going to be able to do so much. I have cnc combustion chambers in my procomp heads it is the cheapest way to make a good combustion chamber. Not the best just the cheapest.
Cnc equals cheap not best quaility. Many companies hand port there heads from the factory ferrari and suzuki come to mind. They cnc first and sendin the handporter guys to make it perfect.
Porting is similiar in skill to welding. You can weld everyday for 20 years and be a master welder. Stop doing it for 10 years and pick up welder again student will run smoother builds than you until you get your muscle memory back in shape. Yes just about anyone can weld but not everyone can make pretty welds. And just like porting robots and computers cant do it. One look at a honda sport bike frame the welds are perfect and clean as can be. These are all hand done by welding gods at honda. Truat me they have tried to teach the machines to weld like them but it doesnt work.
Becoming a great porter is pretty easy get large stackof heads and start cutting. After you have trashed a pickup truck load worth of heads you will be ready for flow bench and dyno results. Yep ok results can be gotten from quicky job but master port work like changing the shape and size is best left to pro. If you want to make the port bigger increase the valve size and make the port that much larger all the way out. Keepingthe same basic shape and size.