C6AER head porting/clean-up exhaust

[Bluedude428]

Hi everyone, I am new to the sight and need some experienced input on porting and cleanup on my C6AER heads mostly on the exhaust. Are the humps in the lower corners there for a reason to add velocity, or are they a hinderance to flow? I know the upper thermatacor humps are a hinderance but how much can they ground away. Just concerned if any possibility of running into water jackets...….so I have been told. Intake info also appreciated Thanks......

[Joe-JDC]

The lower hump is a water passage.  A slight rounding is acceptable, but do not try to remove it.  Most of the port walls are ~.200-.250" thick when new, but old parts with rust/scale leaves them questionably thin in places.  Best to concentrate on the valve job, short turn, and top of the port.  Most of the flow is at the top of the exhaust port anyway.  Joe-JDC

[CaptCobrajet]

Ditto what Mr. Joe said.  Good info he is giving you.

[67428GT500]

I am running ported C6AE-R heads on my Shelby. 2.15 int, 1.65 exhaust. They cleaned up the bowls, exhaust, a bit of chamber work and unshrouding the valves.
My 428 is making 500 hp and it's very streetable. I know there are better choices, but the tall port with the C7ZX dual quads seems to run exceptionally well through all the ranges.
                                                                                                  -Keith

[Bluedude428]

Joe when you refer to "short turn" on your reply what does that refer to? I agree with the  majority of flow being at the top of the port as well which is why "thermatacor" area of the port really gets most of my attention as something to be dealt with. How much of that area , especially the flat spot, can be removed. Is it possible to grind/blend completely smooth? …….Bob

[Joe-JDC]

Short turn is the side of the port that is the shortest distance to the exit on exhaust port, or the valve seat on the intake port.  The short turn on the FE exhaust port(C6AE-R) iron heads can be blended with a .500"/ .750" round stone that can be used in a high speed grinder.  The large radius will only take the minimum material off the short turn, and create a smoother turn for the exhaust flow without hitting the guide.  You do not want to remove much metal in that area.  The upper portion of the port where the EGR fitting hole is located can be ground smooth with the rest of the port roof and not weaken it so as to create a crack when the head gets hot. The bias for exhaust flow will be towards the roof of the port and opposite the hump in the port.  The valve job should extend down under the seat ~.250".  Joe-JDC 

[Bluedude428]

Thanks for the info guys, Joe especially...…..glad to be a part of the FE club!
Joe did you get my PM, just wondering if I got it right
                                                                                          Bob