What is the source of the “aircraft details” in the registration data page? Specifically the engine horsepower and the speed? I fly a Beechcraft Duke and the stated horsepower is 310 when the actual horsepower per engine is 385 and the speed is listed as 150 mph, when the Duke flies significantly faster than that. Who would one contact to correct that data?
The source is the FAA registration database.
There are many varieties of a given aircraft model so it would be impossible for the FAA to list each individual aircraft with its specifications.
That’s probably true, but the FAA database doesn’t include engine power or “speed” specifications. Not sure where FA get’s that info from.
Somehow I think 150 is a bit off for normal cruise… 
The horsepower or thrust is shown in the downloaded version of the registry.
The Type Certificate Data Sheets appears to be the source for speeds. I saw a few speeds around 150 kts listed for the Baron but I don’t know which model they would chose for the speed.
It does; we don’t have the time or energy to make this stuff up.
And happy Cinco de Mayo!
I stand corrected… the N number search on their website doesn’t show those figures so I just assumed…
After looking at Damiross’ link it shows the Duke’s MAX HP as 380hp while the max CRUISE HP is 301 HP, so that clears one item up. As for the 150mph “speed” that’s still a mystery. My guess would be normal cruise is 200-220 mph.
Just to be clear Damiross, the OP has a BE60 Duke, not to be confused with a BE55/58 Baron.
And happy Cinco de Mayo!
Seis de Mayo Zulu time. 
Mea culpa. I got the original poster’s aircraft confused with another poster’s aircraft in another forum.
This is the second time in 3.5 years you’ve made a mistake. You’re loosin it!