My Merlin running at 65in.Hg. and 3200rpm.
Photo was taken at the airpark where I live, Cannon Creek Airpark, Lake City, Florida.

Due to the high manifold pressures I run I recently added a water injection system to it as insurance against detonation. I have momentarily “blipped” the Merlin to 72in.Hg. and 3300rpm which is well beyond normal takeoff power and even war emergency. The QEC (power plant in Brit speak) is from a Canadair Northstar. I‘ve added modern spin-on oil filtration which filters to 5 microns. The unit I use is an industrial hydraulic filter that serves the purpose admirably. A feathering pump is used as a pre-oiler; I obtain 100psi oil pressure prior to cranking. The fully functional propeller is from a DC-3. Being a Packard built Merlin the propeller shaft is a standard SAE #50 spline which offers a whole array of props to choose from. In the photo note the way the front left side (right side in photo) of the trailer is buried in the ground due to torque reaction. A photo cannot convey the unbelievable sound emanating from this engine at any power over about 50un.Hg. It’s no exaggeration to say that the ground shakes and ones insides literally vibrate. No equipment on earth can possibly record the sound, it is simply too overwhelming