wrote:
I was actually thinking what I wrote......MARINE.........so yep, you're
right, I was thinking SHIPS, not boats

Convert THIS one for your airplane:

http://www.bath.ac.uk/~ccsshb/12cyl/

Hmm.
108000HP/2300 tons.
So, around 46hp/ton.

I don't exactly know how this compares with current aero engines, but I
do know that it's about the same as my car, including me!