Thank you guys, great information.

To make me more clear, I should have said : Is it better to prop an engine at 5000 (this is where guys around here prop their 80) or at 6500-7000 for the life of the engine. Knowing my engine will perform in this range, I will use throttle management so that I will not rip the prop in level flight (a thing I do anyway for fear of flutter even if I never experienced flutter).

I should also have added that the plane and engine will fly IMAC advanced and 3D. These new sequences require ALOT of thrust...

From the answers given, my engine should be happier at 6500-7000 and the only drawback would be a higher fuel draw. No big deal, I will fly with 32oz of gas.

Thanks

EDIT: as for fuel draw, I sincerely think that throttle management can do a big difference in that area. I did 15 minute flights with a 140DZ on 30% nitro with 20oz of glow fuel with 3 or 4 oz left for landing.