Its where you remove material from your heads in the chambers and ports for better flow )its actually an art getting lost with all this cnc this and cnc that you can buy). You'd do it for better flow from your heads , which gives better performance and efficiency. Cost varies depending on machine shop. Hope this helps /forums/images/graemlins/thumb.gif
From what i have been told is that if you dont have a flow bench (what ever that is) to check, it realy isnt worth your time? What is the opion of everyone? I dont really know! /forums/images/graemlins/burb.gif
A flow bench is out of most mechanics reach. Most regular machine shops don't even have one. Backyard guys can blend the bowls and relieve the ports (make smooth) buts that about all I'd reccommend in my opinion. /forums/images/graemlins/k5.gif
Unless it a race engine it is pretty much a waste of money.
Guys that race want every pony they can get and spend hours and hours like 40+ on a single head.
They have access to a flow bench to ensure that all ports are the same.
Tedious and costly.
For the engines in our rigs port matching the head and intake is usualy about all you would want to do.
If you start to get wild with a die grinder it can get ugly quick.
Once you start messing with the chambers you have to CC each one to ensure that all are the same.
Otherwise you can wind up with different compression ratios between cylinders.
Port matching is a good way to improve flow, just blend and don't start hoggin them out or you wind up with an anchor.