Kevin, Thanks for your input . This one is copper O-ringed and gasketed.
The Honda was just meant to be a little street rocker and I was turbo charging it just to do it. At most I was running 10 psi of boost with the current setup and the cycle X gasket seemed to be a modern alternative to the copper and O-ring . It seems that these parts are hard to come by on the Honda's not so true for the old 903's. Also, I have a o-ringed J model stock bore block for your turbo project if your interested.