Interesting discussion. I have a bit of experience on the direct drive side as i have a v8 tailwind. It is 300 inch olds, resleved and 300b crank. 10.5 to 1 cr. It produces about 160hp at 2800 rpm. I am seeing about 185 mph at 8000ft density alt. 2800 rpm 10.5 gal/hr.