Recommendations for 340 head gaskets and timing chains?

Hi I am going to be doing a head a cam swap on a 340 that has the lower compression pistons to raise the compression ratio. So I could use any input about head gaskets that have been used recently or with out problems. I am looking for hard gaskets that are thin when compressed to work with the smaller chambered aluminum heads I am going to be using to bring up the compression as much as I can . The 340 is 30 over does that play a part in selecting a gasket?

I am also looking for recommendations on a roller timing chains

thanks for your time an comments
What cc cylinder heads are you running?