Can any one help converting engine to marine

I wonder if anyone can help (I’m new to boating)I have a speed boat it has a pole mounted in the centre of the boat with a ring welded to the top I can only imagine it is for paragliding or pulling something ! it is around 12 foot long it has 4 floor mounted seats with the engine in the centre it has an old ford car engine converted to marine with a jet impeller which I need to identify or is there a way to tell what power the impeller is capable of taking. I was also wondering if it’s possible to fit a motorbike engine and convert or preferably use its radiator instead using the impeller and is there a site I could get diagrams of anything that could help me with these questions.
Many thanks for any help anyone can give.
Best regards
Darren

If it’s possible and you have any answers to the above I would be grateful if you could email me. m2m@talktalk.net many thanks.