No dyno info, but if you hold to the old low tech assumption that it takes around 20 hp per engine per mph, the math would be 40 - 60 per side, but no way to really tell for sure. The boat went a little faster and was a little more responsive. My guess would be more from the CMI's than the intake & carb. Ran 78 before and 80 -81 after. The CMI's were an investment in future work. Put a pair of 525 SC's in the following season, now that perked things up real well, just shy of 100 mph after that change.