You have two options: shift the radiator or the core. Tip, shifting fender core as the way to align the nose to the doors nets incredible results.

The point is moot if you have airspace around your fan. The fan needs to fill the shroud and the fan needs to sit inside of the shroud about half of the blade-width.

If it's undersized, it will cavitate lamf, and you are wasting your time with anything other a correctly fitting fan in the shroud.