Interesting numbers from Dave Morss but some relevant data is missing.

This was in a Legacy or a IV or something else ?

Was the engine an IO-550-N or something else ?

What propeller was installed ?

Standard or tuned exhaust ?

Altitudes were pressure or indicated ?

If I understand the notes correctly the speeds are computed true airspeeds
based on data for a GPS ?

Obviously the comparative numbers look very good and perhaps that's your
point but filling in answers to the above questions helps paint a better
picture.

Thanks,

Ted Stanley