You engine works by being a sealed system, which allows it to build up and disperse pressure where it needs to. Any leaks anywhere can cause a significance decrease in your engine's performance, and indeed, a vacuum leak can prevent your engine from running at all. You need to keep all of your hoses and gaskets in proper repair, and anytime you replace any component, you should replace any relevant gaskets as well. The Accel intake manifold gasket is designed to be used in conjunction with a replacement Accel intake manifold. If you want to be able to use the extra air with your upgraded intake manifold, than you really need to install the appropriate Accel intake manifold gasket. All of the volume increase in the world will be useless if it leaks out, which it will do without the right Accel intake manifold gasket. If you install a replacement manifold, and it is not working properly, you should examine the gasket, to be certain that you installed it. It is easy to forget a gasket, but without the Accel intake manifold gasket, your engine may not run at all, and even if it does, it certainly will not run well. Auto enthusiasts understandably desire fantastic technical support while buying reliable auto parts for their car or truck. Thus, we created an always-online service call center to support all your questions. Nobody likes to pay for shipping, so we offer totally free shipping for each order $50 and higher. If you find a better price, tell us - we will meet or beat any advertised price for auto parts.