The engine number XB33 1312, dates to the model year 1947.
Looking at the pictures, I would guess that this is a home DIY tuning job for a competition class that allowed alcohol. Alcohol runs a lot cooler that petrol, hence the need to reduce cooling by fin removal. The higher compression is needed to get the power out of alcohol fuel, & since there is no pre-igniton or detonation the compression ratio can be as high as like until valves tangle or parts fail mechanically.
There have been large numbers of engines adapted in this way so I think you'd be very lucky to get information on this particular engine.