clive im just wondering why you need a 2mm head gasket? and in my experience ive had nothing but trouble with copper head gaskets. i used o rings and hylomar spray to seal it. the biggest issue i had was coolant leaking from under it as well as oil. i had no issue with keeping 13:1 comp in it with the o rings, but there was always a white coolant stain on the block. this was on my 186 holden engine. have you looked up a cometic multi layered metal gasket. thats what we use on our boosted and race engines at work