This BILLET ALUMINUM, REUSABLE (NOT BREAKABLE PLASTIC) Block Plug is a direct replacement for the MDS Valve on all 5.7, 6.1, & 6.4 Gen III Engines that do not have the Multiple Displacement System. This Billet Aluminum Plug is perfect for engine conversions in street rods, muscle cars and all high performance applications. The MDS Billet Aluminum Plug is totally reusable, designed for easy removal with a slide hammer. The Plug is clear anodized for appearance and ease of cleaning. Please contact Stanke Motorsports with your questions.