Generally, a high performance intake manifold is a part of a team of parts designed to increase engine performance. Remembering that an engine is basically an air pump, that means the more air it gets in and out, the more efficient it is. Intake manifolds combined with things like bigger carburetors, increased compression, better cylinder heads, better camshafts, improved exhaust manifolding or headers all work together to make an engine more efficient. When I say more efficient, I am not talking about MPG. I am talking about volumnetric efficiency, or horsepower to cubic inch ratio. This is why it's so important to match components that all have a common goal. An 850 double pumper on top of a single plane intake bolted on stock heads on an 8:1 compression stock engine with big tube headers is NOT a pile of parts with a common goal in mind. This is why a lot of people are often disappointed. They think for a few hundred dollars, they can have 500 horsepower and it just doesn't work that way. What you need to do is devise a plan of what you want to accomplish. Research parts that will help you acheive that goal. It will take way more than one part to accomplish it.