2.5 Header Collector Gasket Fits Tri-Y

I am restoring a 1965 Mustang GT 350 Vintage Race Car. I change from the street exhaust to the straight race exhaust when going to a race. These collector gaskets have gone through many changes of exhaust sysytem and are holding up like new. I bought a few sets, but after two race seasons I am still on the first set. Great quality and price. Tom Brooks