I am building a 383 for Autocross and street purposes and I bought a set of used AFR (non eliminator) 195s. I put a Fel Pro 1406 exhaust gasket (from my Hooker long tubes) up to the exhaust ports and saw what these pictures show. It appears that a fair amount of material can be removed. I am currently running a 355 with a set of ported trick flows that I had completely gasket matched the exhaust side. But with the flow numbers that AFR has already and knowing that it will not be a dyno or drag strip car, is it worth it or needed to port the cylinder heads exhaust side out closer to the gasket? I'm really not worried about five horsepower gain at 5000-6000 RPM.

 

Porting to the gasket is not what you ever want to do; porting to the opening in the header can help sometimes.
But with the good flowing AFR ports, you have a better chance of hurting the performance than helping it, even if it were "a dyno or drag strip car".
If there's a mismatch, you're better off correcting it on the header and leaving the head port alone.

 

I have read all of David Vizard's books so I have a bit of knowledge about the gasket matching. I know to have the cylinder side a tad smaller than the header side. I just didn't know if like you said I would actually pick up anything or instead hurt the flow pattern.

 

If you need them ported tear em down and ship them to AFR and have them put em in the CNC machine.

Looking at the gasket, I'd check the flatness of your header flanges.
Do you have 3/4" bolts instead of 1" bolts? Aluminum heads need the longer bolts.

 

Even a stock exhaust port can handle plenty of power. The intake port is where the power is at. The entire port should have a rough texture except for the short turn which should be very smooth.

 

AFR was wanting something like 700 last I heard. Not sold on that option right now.

EDIT: Called AFR and they stated that they do not do any porting or CNC services on a head once it leaves their factory.

 

I reread my book on SBC cylinder head modifications by David Vizard. In there it was stated and shown that the exhaust port roof was the busiest area and raising the roof was considered very useful. So I did just that, I opened up the port roof a little bit and put the gasket back on for comparison. I polished up the port exit a bit also but its not well shown in the lighting.