Here at LC Engineering, we get a lot of questions regarding the difference between our Pro Header Kits and our Street Header Kits. Hopefully this will clear up any confusion.
LC Engineering's Street Header is constructed with 1 1/2" 304 Stainless steel primary tubes. This smaller tubing promotes excellent low end torque while still allowing sufficient flow for mid to upper range horsepower. The Street Header has ports on the header flange to run the factory air injection system; these ports can also be blocked off if you choose, just ask your salesperson for some air injection block plates. The Street Headers are also equipped with an oxygen sensor fitting in the connector pipe; this flange can also be blocked off with the block plate that is included in the header kit. These provisions allow us to supply a smog exemption with our Street Headers for those customers that require it.
LC Engineering's Street Headers come in two versions: Direct-Fit and Custom Fit. The Direct Fit version come with a 3-piece adjustable connector pipe that is designed to connect our header to your factory exhaust (connector pipe bolts directly to the front of the stock catalytic converter location). The Custom-Fit kits include a shorty stub flange and an oxygen sensor install kit. This kit allows you to connect our header to your custom exhaust. The stub flange will bolt to our header and weld to your exhaust. The oxygen sensor install kit comes with a weld in flange, gasket and hardware.
The LC Engineering Pro Headers are made from 1 5/8" stainless steel tubing. This larger tubing allows for maximum flow at higher RPM ranges. This is perfect for high RPM race applications: drag racing, circle track and even some off-road racing. While the long tube design does retain some low end torque it will sacrifice a lot of torque as compared to our Street Headers.
The Pro Header is also equipped with an LC Engineering exclusive merge collector design that allows for optimal flow through the merge collector and out of the header. This are is extremely important for high RPM application to ensure that there is not excessive back pressure to prevent your race engine from breathing like it wants to.
The Pro Headers have no smog provisions on them so you can't install factory air injection tubes to these headers. They also have no oxygen sensor flanges so you will need to install a flange in your exhaust if you want to run an oxygen sensor in your exhaust. Lastly, the Pro Headers have no connection to the factory exhaust. Due to their extreme flow potential they can be run as an open header or used with a custom free flowing exhaust system.