Hi PB.
Assuming there is nothing to the contrary in the POH, you should get maximum speed at full throttle/max rpm, and mixture adjusted just enough for smooth running(if necessary) Most normally aspirated Lycomings can run at these settings until the fuel runs out.
Although it is conventional to run with square power settings, this is just a convention, and you can run most normally aspirated Lycomings with up to 4 units 'oversquare' eg. 29"/2500rpm.
The fuel flow in USgph at full throttle and max rpm should be about equal to the max horsepower divided by 10. eg. 200hp = 20 USgph.
Do check the limitationms in your POH though!.
MJ
