Well what engine is it for? Big block? Small block? Slant six? Chevy? Ford? Slowpar? Briggs and Stratton?
Really dude. You may as well have asked "will this red thing help my car?"
Just because you know what you're talkin about doesn't mean everybody does.
This is the description from Summit.
"Offenhauser Dial-A-Flow intake manifolds take a really unique approach to power selection. They let you pick the performance level you want, simply by changing the specially contoured Flow Control inserts that sit in the plenum to regulate the fuel/air mix. As you move from Stage I to Stage III, power increases get bigger and move up the rev band. Inserts can be custom-shaped with a die grinder or carborundum to change performance characteristics. Power bands spread from 1,500 rpm to nearly 9,000 rpm."