What engine in my B6001?

Hello everyone,
I am new to this forum as I just have bought a gray market B6001 on Mallorca, Spain. I was told by the previous owner that the engine was not the original but a stronger one. He could not give me any further details and I am not fluent in spanish so I could not cross examine him.
I tried to find an engine serial number on the crankcase, right side. But I could not find any! The tractor serial says B6001-13109.
I can see some numbers on the engine block as you can see on one of the pictures below. It is D75 and 930.
The cooling is by pump and not natural circulation.
Anyone got a a clue what engine it is? Can I do more to identify it?
Thanks in advance for any help!
Anders

Thanks North Idaho Wolfman,
I am now in Stockholm, Sweden but I will return to Mallorca and my Kubota at the end of January. I will try to find the number then, and get back to you.

Anders

Wolfman,
I was looking through my tractor pictures and I found one of the engines right side behind the fuel filter. There is a cast in number on the engine block and it looks like 927cc. Is that the number you ask for?

Anders