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 2 units required. This procurement is critical as the item is flight critical, necessitating government source approval prior to contract award, and only previously approved sources will be considered for solicitation. Interested parties must submit detailed technical data and experience documentation as outlined in the NAVSUP WSS Source Approval Information Brochures, with proposals due within 45 days of the notice publication. For further inquiries, potential bidders can contact Connor C. Lewis at (215) 697-4757 or via email at CONNOR.C.LEWIS@NAVY.MIL.