new exhaust gaskets for stg 1 heads they are 1/8 inch thick. these are made from flexable graphite material and are good to 3000 degrees. also they give a money back guarantee if not completely satisfied i have 4 sets for the 455. the chevy guys love them and use with great success. i am going to have them make them for the stg 2 heads also. 38.00 a pair