These fit the 8.3 MBR/Fontana/Arias with a 2.50" x 2.00" rectangle exhaust port. Ports are embossed to offer a crush when the header is tightened down to provide a superior seal.
Exhaust gaskets are set up with ten 3/8" stud holes and are sold in pairs.
*** NOT DESIGNED TO WORK WITH MBR MTS1 HEADS THAT USE 5/16" EXHAUST STUDS ***