The Department of Defense, specifically the Department of the Navy through NAVSUP Weapon Systems Support, is seeking proposals for the repair and modification of diesel engines, identified by NSN 7R-2815-124117665-SX, with a quantity of six units required. This procurement is critical as the item is flight critical and requires Government source approval prior to contract award, meaning only previously approved sources will be considered for this solicitation. Interested parties must provide comprehensive documentation as outlined in the NAVSUP WSS Source Approval Information Brochures, and offers lacking the necessary data will not be considered. For further inquiries, potential bidders can contact Connor C. Lewis at (215) 697-4757 or via email at CONNOR.C.LEWIS@NAVY.MIL.