I guess it has to do with what your total combo is and if you are going to run aluminum heads and headers or not.

My intake is untouched from the factory. I have a 523 stroker (440 source kit and .060 over) in my six pack Super Bee. I had this car built to basically be legal for F.A.S.T. racing if it ever comes to be in the southwest. My engine is a 73 and did not have the 906 heads but rather the 452s(?) so we used them as they are pretty much the same heads anyway. it has a roller cam, balanced and blueprinted, all the Pro Max mods, around 10.5 CR etc. The top guys in the F.A.S.T. racing are running around 14. t0 1 CR but i wanted to be able to run my car on the street as well. The engine builder told me that the intake is really not such a big bottle neck in my case as i am running factory exhaust manifolds and full exhaust. I have not finished my car as it still needs paint so i have not had it to the strip, but it "feels" it is a 11.5 second car on drag radials or maybe a little faster.