Storage Block Off Exh. Plates - GM LS

The MOROSO Storage Block Off Exhaust Plates for GM LS-series engines are one-piece aluminum blockoff plates designed to seal off unused exhaust ports on LS engine applications. These plates provide a clean, factory-finished appearance when running a single or dual exhaust configuration on an engine that originally featured multiple exhaust outlets. Supplied as a pair, they eliminate the need for exposed, open ports while maintaining the engineered flow characteristics of a properly tuned exhaust system.

Constructed from aluminum in natural finish, each blockoff plate measures 8.8 × 0.5 × 18.25 inches and weighs 0.67 pounds per pair, keeping installation lightweight without compromising structural integrity. The single-piece design eliminates assembly complexity and potential leak points, while the aluminum material resists corrosion better than untreated steel alternatives. LS-series engines have become the standard platform for both OEM and aftermarket builds across trucks, performance cars, and custom applications, making exhaust port management a common requirement when upgrading or reconfiguring intake and exhaust systems.

Builders and engine shops rely on blockoff plates to achieve a finished appearance during engine swaps, forced-induction conversions, or dual-exhaust retrofits where stock manifold ports no longer align with the new exhaust path. These plates seal those orphaned ports cleanly, preventing exhaust leaks and maintaining proper scavenging in active exhaust runners. The MOROSO part (MPN 25157) is a recognized OEM-adjacent solution trusted in both street and competition builds where aesthetic finish and functional integrity matter equally.