Description CSF 8404 Second Fuel Rail Kit for CSF S58/B58 Manifolds For those looking to run dual port injection, CSF offers a second fuel rail kit. The CSF #8404 Fuel Rail Kit comes with all the necessary mounting hardware and features the same -8 ORB fitting as the primary rail. It can be set up as a return or returnless system. Applications: - Fits the CSF 8401 and 8401 Air-to-Air Manifolds only (8401 / 8402)