Copper Seal Collector And Header Muffler Gasket. Copper Seal Collector And Header Muffler Gasket; Triangle; 3 Bolt Holes; 2.5 in. Dia.; 3.5 in. Bolt Circle; 3/8 in. Bolt Hole; Each;. Now an important part of Holley Performance, Mr. Gasket continues to expand application coverage with more and more new products for race cars and muscle cars alike.
