The engine shots are between 13-15 minutes.
https://youtu.be/rxq_EWlhRd0?t=781
It looks like they cast their own aluminum block then bolted on the head and accessories from an NA OM603.

And the story on Jalopnik.
The Living Apostle Who Sold The Media On The Myth Of ‘Ghana’s First Car'

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CENSORED due to not family friendly words