Sounds provocative, but you might-could have advised what prop your mere 320 twirls.  ; )

Elsewise, have you a cruise drag coefficient estimate for this airframe?

 

If ever tracking southward from Aurora please drop in at KGRE for a viewing an lunch.

Redhand,

 

The ballpark Drag estimate number is "small to very small".

 

The prop I am currently using is the Lancair recommended Hartzell CS prop (HC-F2YL-1F hub, F8468D-14 blades).  The Hartzell scheme was to take an existing 84" prop and rid it of 14" with some taper of the thickness as the tip chord was approached as the blade did not have to carry all that extra length.  This results in what appears to be an wide bladed prop that is the rage these days.  My prop is slightly different in that my blades are actually from an old 84 inch prop with 14" lopped off.  Thus, it weighs more with a very thick blade at the tip.

 

Hmmmm, you are a mere 57 minutes away (at cruise, quicker at WOT - 2650 RPM).  Are you ever at GRE during weekdays as Grayhawk is retired and does home maintenance projects on weekends whilst acting as an airport bum during other times.