MOROSO CHEVY DECK PLUG KIT - MOR-37800

Upper cylinder wall distortion is greatly reduced when these 3/4" NPT plugs are installed in the water passage holes in the decks of Small Block and 90 V6 Chevy engines Water holes must be tapped before the plugs are screwed in; block must also be decked after installation Plugs also restrict water flow to the cylinder heads by reducing size of water passage holes to 5/16".