Exactly............what He said.

 

I would think the HP increase would be the most noticable on a more restricted engine such as a 2 bbl carb or restrictor plate engine or even a dual plane manifold if it is a scavenaging effect(Bill's 350 had two of these). So what you are saying makes sense although I wonder how many of these huge (10 to 15%) hp gains across the board are fairly quantified. All things being equal other than swapping two cylinders and gaining 40 hp you would think it would have been the best thing since sliced bread and all the cam companies would have been pushing it.