Well no kidding, I didn't say they would, only that certain magnum manifolds WILL work. I'm not sure what your point is other than you feeling a little jumpy this morning.
It's a much more cost effective way to get some "decent" flow on a street car. For what the engine is, they will be loads better than the 273, and headers, for that engine, aren't going to do much more and not enough to justify the cost in my "opinion" and so I offered an alternative that he migtht not have otherwise explored.
At the end of the day, I don't have a dog in the fight, nor do you. So again, not sure what your point is.