Need some advice on some cylinder head gaskets

For long term strength concerns of the block, I would consider a minimum of having ring dowels installed in the caps and block along with cap straps or a Hughes engine girdle (I would install ring dowels either way). My machine shop operator made a pro charged 318 based 391 live under a lot of boost with water meth injection (600+RWHP) and cap straps with ring dowels. It regularly went 9.80s in a Duster. I really don’t know where you’re expecting to lose power other than maybe barely off idle and low rpm cruise. The only way it won’t make more power when it’s coming into boost is if it breaks.