My apologies for not replying sooner.

Prop tests conducted 2 weeks ago gave the following numbers. All numbers are with the engine thoroughly warmed up with over a minutes run time before the reading was taken:

Mejzlik 28-10, 6850-6900
AM 28-10, 6900+
Menz-s 27-10, 6900+
Menz-s 28-10, 6250-6300
Mejzlik 29-10 (squared tips to 28"< purpose is to reduce rpm but still have a wider blade for good pull) 6400 rpm

These are on an engine that does NOT have a "tuned" exhaust, using 3" headers and BIG mufflers to quiet the noise. Loudest prop dB'd at 94-95 db's at 25', quietest was about 90-91 db's