Thats thrown me the only ones i have seen look like this.
The gasket looks correct; ie relieved for the 'O' rings and the counterbored rebates in the block.
What cc is stamped on the front right of the block?
Not sure what to say about that,..... i will defer to someone with better knowledge.
From Z Power site
https://www.z-power.co.uk/merchantmanag ... php?pId=34
CYLINDER HEAD: THE O`RINGS THAT WERE THERE TO CONTROL OIL FLOW DID`NT. WELL THAT`S NOT EXACTLY TRUE. THE OIL FLOW ENDED UP OUT OF THE HEAD AND NOT THE OTHER WAY ROUND. OWNERS IN AN EFFORT TO TIGHTEN UP THE HEAD NUTS TIGHTENED THE CAM CAP BOLTS INSTEAD AND BROKE OFF BITS OF THE HEAD. MODIFIED CAMSHAFT END SEALS AND MODIFIED O`RINGS SOLVED THIS PROBLEM EVENTUALLY. LATER MODELS WENT BACK TO A HEAD GASKET WITH NO O`RINGS. SO MUCH FOR PROGRESS.!!! OIL LEAKING FROM THE HEAD GASKETS WAS TO PROVE A PROBLEM FOR MANY YEARS TO COME.
P.S. that looks a little like a high compression unitrak head with the bi-spherical combustion chambers.
AL