Ian - an open exhaust reading would be nice -as would a proper torque and rpm curve- for lookee see.
Problem - what would you do with the info?
to most new flyers - the torque and power (rpm) mean nothing .
as for a dyno - --on aircraft engines -this is not really of much use - the why is that there is very little load at low rpm- a reading on a series of "loads" tell one a lot more about an aircraft engine.
the load , is typically a stubby prop looking thing that requires a known amount of torque to turn at a given rpm - these have been around for many years
Some engines run best with certain exhaust setups -
Some are designed specifically to run correctly on a tuned system -
A chart with each engine -giving optimum setups would be nice -
The use of std loads in not used here but at one time the load props were available from Germany .