Get a graphic engine monitor, and you can see for yourself how your particular installation likes to run. In my case, with a Lyc O-320, 2450 rpms results in the best balance of egts, (all four cylinders within 25 deg), decent fuel economy, and reasonable chts of 340-360 deg. Every installation is going to be a bit different, especially after a couple decades since leaving the factory. Just overhauling my carb made lots of difference. (for the better)