9000 RPM from a RELIANT ROBIN ENGINE - What could go wrong!

My Jeffrey 750cc historic sports racing car has a Reliant 748cc, all aluminium, OHV, 4 cylinder engine from a Reliant Regal/Rebel/Robin or Bond Bug.
This one has been modified with a race camshaft, lightened rods and rocker gear along with a front mounted dry sump pump.
The engine was race prepared some 30 years ago by Graham Bolton and has had only minor maintenance since.
The engine regularly revved to 8000rpm, however, since changing the final drive ratio to 5.3:1 and fitting a Reliant Regal gearbox with shorter gear ratios, the engine has been revved a bit closer to 9000rpm!
At the Doune Hillclimb in September 2022, the engine finally cried enough and broke the timing chain.
I have yet to strip the engine down to check for other damage.
Still Photograph by: Andy Hamilton