Those flow numbers are about what I have seen as well.
The cam application does depend on what you have done to the heads though.
The original heads have a built in "torque ring" just under the seat. They were originally put into the 70 Boss 302 heads because of "customer complaints" on the '69 Boss 302's with the 2.21 intakes as being sluggish.
I don't have any flow numbers on the heads with the "competition" cut under the valves and can't get any of my friends with flow benches to comment on if there is an improvement or detrimental effect on that modification but my A3 heads flow 330 @ .600 and were built without the torque rings.
Even so the flow numbers will not indicate IF the engine can use the additional flow to make more power. It's entirely possible that the additional flow only makes more power at above useable rpm's of the engine.
My information shows maximum flow at between .570 and .580.
As you point out and as I had mentioned, the issues with the iron heads generally stem from the exhaust port configuration.
The OP's cam is also a roller which uses a little different criteria and shows different results at different rpm's. They typically provide more low end torque then flat tappet cams can.
The overall timing of that cam is not radical and so what if it has more overlap? It isn't going into an automatic transmissioned car and isn't being used on an individual runner intake manifold.
Personally I think that it just would run just as well with about .025 to .030" less lift. Probably .570 to .580 would be about what to aim for which would be much kinder on the valve train components.
I have never heard of a "perfect cam profile" anyway. It just depends on what you find acceptable and not acceptable, which means you have got to run it and find out if and where you made a mistake in judgement. You can always change it for a better solution.
