Maybe KM/h below sea level.

Isn't the Commander a single engine Duke?
Looks good, comfortable and slow as hell for the power it has.
One good thing, it can fly LOP.

V tail impossible to beat single engine.

I was Jim Ricjards original partner on the experimental 'Super Commander'. It's till flying. 165 KTAS is about it. He is still working on some aerodynamic improvements, but the wide fuselage can't go through the air much faster with that power plant. It's an impressive bird no doubt.

I'd say that information is straight from the horse's mouth.

165 KTAS is not far off. I own N4874W a 1977 straight 114 modified by Jim Richards to Super Commander configuration in 2010.

I file 165 kts and get between 163 and 167 depending on altitude (8 to 10K), weight of AC and OAT. Fuel flow for that is between 15.5 and 16.5 USG. This setting corresponds to between 65 to 67% power.

I have pushed the power a few times for various reasons. I got a max of 178 KTAS. OK for short bursts, but not for sustained flying. FF then becomes prohibitive at roughly 20+ USG.

The early straight 114 Commanders are lighter than the later serials for the 114B, TC and 115's. These airplanes often have AC, dual alternators etc. They tend to be slower.

Rate of climb is exceptional. I cruise climb at 90 KIAS and see around 1500 FPM. That is for a normal South FL day (90+) and full fuel. Up north, I have seen 1700 to 1800 FPM.

I do have another mod which aligns the elevators with the stabilizer. The mod yielded a couple of knots on average depending on altitude. That mod is also offered by Jim Richards.

Overall, this is a great airplane. Wide, comfortable and performing. Landings are easy thanks to the trailing link gear. Baggage capacity is excellent (200lbs) with a wide baggage compartment door. I load 2 small folding bikes easily plus luggage. Useful load is 1006 lbs in my case. Full fuel yields 598 for people and baggage.

And I got the cockpit to look like I wanted... Photo attached.

Richard