I understand and I am not disagreeing. But, you simply can’t lose horsepower if if you increase compression to a smaller degree. Especially when, the stock compression ratio, is what 8 to 1 ? I would think. If said motor is making 300 hp and you make changes to the head only on that same motor. It would have to have slightly more power ? I agree, to know what the exact compression ratio would be. You would have to know every specification. It’s not like a simple head modification or head change would over shoot a 10.5 compression ratio. Now requiring it to run on race gas only. Unless, a very high lift cam was installed. Maybe I’m wrong.