Mr. Walker, the bore & stroke of the Wright Cyclone R-1820-97 engine used on the B-17 is,
bore: 6.125" (155.6mm) stroke: 6.875" (174mm)
actual displacement is 1823 cu. in.
1200 horse power with exaust driven turbosupercharger.
This is interesting to me too, being a mechanic.
bob levandoski