"The position of the stagnation point varies some with angle of attack and sideslip angle, but for typical piston-engine cowlings the stagnation point is at, or slightly below, the most forward part of the front face of the cowl. This is where the cooling air inlets should be placed for best performance.

There is also a region of high local air pressure just below the spinner, and this is a good location for an induction air inlet or an oil cooler inlet."

https://www.kitplanes.com/cooling-inlets-part-2/