If the TF heads really flow what they claim, and the port volume is only 240cc's, then I think these will be pretty tough to beat on a pump gas hot street/strip 440-470 type combo.
If they actually flow 330+, that's 15+ better than a MCH CNC stealth on my bench, and 12cc's smaller port volume and a bigger valve.

I have numbers from my bench and your stage 6's, so it will be interesting to see how they compare side by side. IMO, what those 6's really had going for them was decent flow from pretty small port volume, which I feel is a good combo for moderate cube pump gas motors running in heavy-ish cars with closed exhaust systems.

If the TF's flow 330+, then I think the real apples to apples heads to compare them to are going to be the Hughes std port EZ's where they CNC the chambers and fill in the lip on the intake roof. But those cost $800 more.
Both are std port heads, heart shaped chambers, std height ex ports, std rocker arms.
I guess you could include some CNC ported 75cc edelbrock heads too, but they are also over $500 more than the TF's.

That would be a pretty fun dyno shoot out. Those three heads on like a 505 pump gas short block, try a couple different intakes on each set of heads.....see how it all shakes out.