Boston Whaler Trophy 17" Notched Transom

[Hoochymama]

Am I ok putting a long shaft 40 or 50 HP motor on a 17" transom? or am I stuck searching for a ss remote control electric start outboard for my 1970 Boston Whaler project?

I am having zero luck rehabing my dad's old 1970 Johnson 40 HP motor he used with the boat.

Thanks.