Changing just the motor on a pump does not change the performance of the pump. It is the impeller and wet end that determines performance of the pump. The motor is just there to turn the impeller but must be sized correctly for the impeller. If you don't change the impeller, the motor size should not change.

But when it comes to circulation and filtering, even the smallest pump is usually sufficient for the largest pool and usually the best choice. Larger pumps require larger filters and just use more energy without much benefit. I have a 1/2 HP pump on a 20k pool and it is more than sufficient for cleaning the pool.

But lets start with why you think you need a larger pump.