Paul57

I am giving serious consideration to cleaning up my 317 head ports rather than springing for a full blown CNC port job. Since I have a low lift/rpm (.531/5500) cam, my plan is to just smooth everything out and try to put a little more radius on any corners/edges.

I have one big question I am hoping someone can help me out with. On the intake port, the seat sticks up quite a ways into the port and leaves a big lip, in the port. The seat looks to be over 1/4" thick/wide but I suspect that I would need to remove at least half of that to get a smooth transition. Is it OK to remove that much or does it stick up that much on a full CNC job too?? There is a bit of a tumor (for lack of a better word) in the combustion chamber next to the spark plug...I suspect that it should be OK to remove that since the CNC picks I've seen don't have it either, correct?????

NemeSS

iTrader: (127)

if youre asking these kinds of questions, it would prolly be best to leave the heads alone and spend your $ on a spec'd cam.

ramdaspadhye

iTrader: (3)

You need to mill those 317's and have Pat G spec you a cam.

Cliff

iTrader: (19)

If your learning to port, I would suggest to have a 3 or 5 angle valve job and leave the heads alone. If you have someone who can help you grind the bowl then get there help. You can mess up the velocity.

Paul57

I don't really plan on messing with the bowl too severly other than to smooth out the casting.
I really just wanted to make the casting very smooth...put a larger radius on the bottom of the valve guide casting area, take the edge off the intake valve seat, smooth out the ridges on one side of the exhaust casting and remove the tumor from around the spark plug.
Do you really think this is more than I should tackle. Just for the record...I am not a hack/butcher ...I know there are a lot of them out there, in any occupation. I believe in precision and understand the need for smooth transitions in air flow. I just don't have all the intricate details of this head design and was hoping to get some good guidance.
My motor (LQ9) is 10.08 to 1 now and I'm planning on running a .010 thinner gasket (.041) along with milling .010 or so. That should get me near 10.5, correct???
As much as I would like a different cam, it probably isn't going to happen. I got this one for $250 brand new...it is a Crane.

Paul57

I am planning on a 5 angle valve job.
Also, I am considering under-cut valves but am not sure of the going price and how much they will improve the flow.
I guess the bottom line is...I am trying to add flow/velocity (even if it is on a budget) without any serious increase in port size/cc.