In my experience and observing dyno pulls on YouTube (such as Nick's Garage), it is HP under the curve that is most important. Peak HP is for bench racing, torque under the power curve makes the vehicle move. That being said, look at a few of the articles on intake selection such as DIY Mopar. Building Mopar Engines for Performance: Intake Manifolds - Mopar DiY Or the Steve Dulcich article on manifolds. Mopar Small-Block Intake Manifold Flow Test This 340 build article is also interesting showing how different components impact HP. http://www.moparmusclemagazine.com/techarticles/engine/mopp_0102_1970_340_high_performance_mill_dyno/index.html
This article has some dyno pulls which if analyzed will give HP under the curve data. Excel will do this easily. Modifying And Testing A Dodge 360-Cube LA Small-Block On The Dyno
There is one more article that I remember that compared many manifolds with dyno numbers. the RPM Air Gap had the most area under the curve in that analysis so would provide best overall performace although another manifold did have more peak HP.
But some of the selection is all about image too, so chose what you think works best and runs hard. Most selections will be within 5 HP of each other anyway.
