Horsepower Estimates

Race them against each other and see. Feeling and being are two different things. BTW, the .509 is a larger cam than the .528, it's "Hyper-eutectic" pistons, and if the engine was built for NO2, you may want to verify the top ring gap was set properly if you are not sure. Being that the shop used those pistons knowing you were planning NO2, I'd verify they set the gap right...