Performance Exhaust Overview: A performance engine is an integrated affair. When you modify one set of components, you have an effect on other systems. On a mildly modified engine, a minor upgrade in either the cam specs, exhaust system, or intake can be done independently. For performance, camshafts work best when integrated with upgrades in the exhaust and intake. The exhaust system is probably the first area to improve on any engine, because this will only enhance future modifications. The study of Physics tells us that we usually can't get "something for nothing", but when adding headers and improved exhaust components to an engine, we almost do. The improved exhaust flow and velocity derived from tubular headers and free flowing mufflers is one of the only modifications you can make to an engine which will improve both power and fuel economy. Description: These outstanding headers are built especially for Motorsport to our strict specifications. The thick exhaust flange is flat machined to promote a consistent seal. It also prevents warping and eliminates the need for spacer height modifications. Exhaust ports have high-quality welds to ensure leak-free performance. We use 1 1/2" primary tubes to ensure increased exhaust flow without any performance loss. This header comes with a flanged adapter to fit to the stock catalytic converter (If you are building a custom racing exhaust not using the converter and would like a 2 1/2" adapter, please give us a call for specifics). Special installation gaskets are included (do not use original equipment type exhaust gaskets with headers). This header configuration is for original 81-83 280ZX Non-Turbo cylinder heads only. Includes threaded fittings for the EGR Valve and Oxygen sensor.