If your motor makes 1.2 HP per C.I. how much HP does it gain 451x1.2=541.2 HP compared to 1.2x470=564HP.
Of course if it makes more or less HP per C.I. the results will vary accordingly
I'm not sure about how much the torque gain and PEAK RPM for both torque and RPM are affected by stroke changes
I do know that on my last pump gas street and strip car increasing the stroke .050 (went from 4.25 to 4.300)helped it by .2 ET and 2.5 MPH