Here is an approved flight manual supplement letter from the FAA.  Model 35, 1947 and 1948 Bonanza. This is for the now common configuration of an E225-8 Engine and a Hartzell Hydraulic Propeller. The E225 is "officially" not authorized to operate at the higher limits the engines are capable of in the Model 35. The RPM limitations were originally determined to be applicable to the original engines such as the E185-1 engines. The original Propellers were also a factor, with the wood blades, they were set up to operate in the 1850 - 2050 rpm range with a 2300 max take-off. Be sure to check your Tachometer and Manifold Pressure Gauges for correct markings for Your model Bonanza.

E225-8 Engine

and

Hartzell HC-A2V20 Prop

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