Brian, are you going to provide TF with some feedback on the head porting? Be interesting to see how well they understand the cam timing sensitivity. I'm not sure if that is a feature or a bug to them. I think it is a bug for racers although it might be a feature for street guys.
I didn't have the capability of porting the heads so I had to make my changes with the cam. Between Dwane and myself we found a solution. I was surprised at how sensitive the TF heads were to cam timing and lobe profile. If you don't get the right combo the heads aren't happy
I don't think they care what I found, and they aren't asking for any feedback. It's not a bad head, but I needed to make it work for low'ish compression and this CID so that's why I reworked them. In the process of doing that, I found at least a few things that I'm sure are causing the heads to act like you observed.
I spent quite a few hours on just finding and correcting the problems, so I'm keeping them close to the vest...but if you start measuring the ports out in the critical areas it becomes clear where the problems are...but until you actually make the changes and run the engine there's still a bit of doubt about the power they can produce. And I was not able to make them as large as I really wanted to in certain area's to get the air speed down, as the castings are really not as thick as I had hoped. In fact, you have to be very careful because they are thin is quite a few area's from a porting stand point. They aren't thin as they come out of the box, just a bit too thin to really open them up to work with larger engines or more rpm.
