*** IN STOCK SHIPS TODAY *** RBS carries a full line of NRE/Noonan copper exhaust gaskets. These gaskets are made from soft copper and will seal the header to the head with no problem. Gaskets are sold in pairs and fit NRE/Noonan cylinder heads.
These have a square shaped exhaust port with 2.130" x 2.450" dia. hole and are .050" thick. Gaskets are profiled to shed excess material and save weight.