340 marine engines.
I had a 340 chrysler marine in my 1965 Pembrook mahogany hull cabin cruiser . It was a good motor . The boat was a single screw 28 ft and went thru the water real nice.It cruised at around 2500 RPM and drank around 8 gallons of fuel an hour Just gave away the service manual for Chrysler Marine ( genuine MOPAR ) to a friend .It covered 340 and 318 . There was also a 225 marine engine used in smaller light weight boats . Most of these motors were salt water cooled so be aware of that if you are going to build one for a car , rust never sleeps .