Thinking outside the box
I guess my main confusion here is, are these new hi-tech gm heads a true bolt on for your typical 70's 350? If not, then the point is moot. I'm not a cylinder head expert, but I think the reson for the taller intake ports on the modern stuff, has to do with it being fuel injected.
That being said, I don't see anything wrong with wanting a better performing head that would be a true bolt on. I think the problem is, we don't always see all the proto type stuff. Who truley knows what is & has been designed behind closed doors. One thing for sure, its not going to done by Mother Mopar. This is going to be done by the aftermarket & individuls. Fifteen years ago, you could count on one hand the number of mfr's that produced heads for the small & bigblock Mopars. That has all changed now, lots of great speed parts now for Mopars.
Now as for comparing the 350 to the 360, I believe the 360 (using bolt ons) will outperform & out live the 350 by a long shot.
I'm a low buck guy who have been Drag & Street racing for 30 years, I have won many races with less perfomance componets than my fellow brand x'ers.
Now theres always going to be more suppliers for the gm stuff, this is very simple, VOLUME.
The thing that always got me was "ITS CHEAPER TO BUILD A CHEVY". Well lets see, aftermarket block, heads, crank, rods, pistons, I just don't buy that logic.
Let me get back on topic, the mans concern was the new gm heads, if you can't retro them to the early engine, I see know reason for comparison.