340 Head Gaskets

Starting a 340 +.040 stroker build race only. Have my kit all but the pistons so I don't know the correct compression number just yet,but should end up around 12-12.5 range. I'm running Eddy heads with studs,block will be poured with Hard Blok & Girdle on the mains. What are you guys running for head gaskets? Copper? Should I O-ring it? With the bolt arrangement on small blocks just wondering what works best. Newbie here to small blocks. Thanks