The plugs I pulled from mine were aluminum but too thin to weld I think. Mine was a 3X1 and I cut it down to make a 2X1 for a 4 cylinder. I welded an aluminum pipe bung in the front hole and another one on the cover plate on the bottom. You could remove both plugs, weld in bungs for water in and out and use a flay plate on the bottom where the exhaust used to enter. Or you could just JB weld over the old plugs. A
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