You have to find out, where your o-ring is. Make sure the o-ring did not land in the fire ring around the bore on the gasket. Hopefully you have an old gasket to compare to. Once you find out, you can order your gaskets. Also you have to remember if the copper head gasket will indent the aluminum head. If it does, you will have to shave the head to re-install it if you vent. After a few shaving, then you open a can of worms.
My experience:
I had my GN1s o-ringed, and Champion says to use the Felpro 1026 gasket. I can't use the 1026 because the 1026 has steel across the top of the gasket thus preventing any clamping force for the o-ring to "bite" into. I had to use a stock gasket. I am a firm believer in using the stock gaskets, they have been proven countless of times under high amounts of boost.
