I have noticed that everybody has a 52mm throttle body, and some kind of pcm. I do know what these are but i want to know why and how they work better. ANd where i buy them at and for what price? Any info would be great. Thanks
The throttle body is the modern version of the carburetor on top of the intake manifold, it is the device that opens up to let air into the engine.
5.2L/5.9L motors come with a twin-50mm throttle body that has a 48mm torque ring inside the bores. There are two different types of aftermarket throttle bodies - a modified stock unit or a replacement billet unit. Companies like the Fastman open up the OEM bores to 52mm, replace the blades, clean up the ports, etc. The billet replacement units are designed to be a certain size during production, and typically flow more air with less size. People who are stock or near stock will want to try a 52mm modified OEM unit or 50mm billet unit. Once you get a full range of bolt-ons installed it is best to upgrade to a 53mm modified OEM unit or 52mm billet unit. People with superchargers or turbochargers can take advantage of the big bore throttle bodies, up to 58mm bores.
The 4.7L engine comes with a single 65mm or 68mm throttle body, depending on what year you have (older ones are smaller). You can replace your unit with 68mm, 70mm, or 72mm versions.
PCM flashes upgrade your computer programming - it depends on what year/make/model of unit you have to determine which is the best course of action.