Michigan Motorsports Injector O-Rings Set of eight (8) custom molded injector O-rings designed to allow you to install standard injectors into the production GM LS2, LS3 and LS7 intake manifolds. The LS2, LS3, LS7 intake manifolds have a different diameter injector bore cast into the manifold. If you try to use standard injector O-rings you will have intake manifold leaks at the base of each injector. The same will happen if you try to use the O-rings from the LS2 injectors on standard size base injectors. This is because the LS2 injectors have a different outer diameter (OD) at the injector O-ring at the base of the injector. These O-rings are only needed on the bottom (intake manifold side) of the injectors. The LS2 and LS7 fuel rails have the same size injector bore as LS1 and most other fuel rails. These injectors O-rings are molded out of Viton like the production O-rings. Sold in sets of eight (8) pieces