A-3944593-AI Bolt; Exhaust ManifoldOne New Aftermarket Replacement Exhaust Manifold Bolt for Cummins B Series Diesel Engines This exhaust manifold bolt secures the exhaust manifold to the cylinder head on Cummins B Series diesel engines. Replaces OEM part number 3944593, this is a flanged hexagon head cap screw designed to maintain a proper seal through repeated heat cycles in high temperature exhaust environments. Sold individually; 12 bolts are required per manifold. Specifications