[Nine8Six]

If you can find out the "smallest" wall thickness of the cylinders and its material composition, I can quickly run a sim and let you know what sort of psi you'll be able to run 'safely' within, both during detonation and compression for that 986.

Those 986 pistons and conn rods also (material), especially at the pin. Whether it is a conventional alloy, cast or not. That pin pivot point is where the force will be greater so the material of the pin is equally important. Shall it fail, the piston pivot point will let go before the pivot on the crank.

I bet the rings are heat treated 8620 conventional alloy already so this should already be good enough (just guessing here).

Start with that mate, obviously there are other pressure points that needs consideration but if the above sim fails there is no point carrying further analysis.