This led to extensive flow testing of a stock type intake and Plenum. It is common knowledge that leaner cylinders are more prone to detonation than richer cylinders. So Hemco set forth to enhance airflow to all cylinders while trying to increase equalization of air flow to all ports. A whole new casting design and concept was developed to achieve this effect. All of these concepts generate a sloping angle to the rear of the Plenum, which aggravates the condition already existing in the stock Plenum.
Air is forced into the rear cylinders while the front cylinders are still starved for air.
This design causes the intake manifold to react as if a throttle body was sitting on top of it and increases the total CFM airflow even through a stock throttle body. A seventh injector was developed to richen, or add fuel to the rear cylinders. With the Hemco system a seventh injector is not required because air distribution to all cylinders is enhanced. After selling a couple hundred Plenums and hearing of the increases in MPH and better ET's , the people at Hemco are so confident of their product that we offer a money back guarantee if you are not satisfied with it's performance. You don't need a 10 second car to take advantage of the Hemco Plenum .