Dave,
I have an APC 17X 10 on my 140DZ now and it peaks out at around 8,450. I run it at 8,300. I tried a Mezjlik 18x6 and it ran up to 9,300. I prefer to use Mezjlik and the largest diameter lowest pitch that works, but I remember reading that you recommend keeping the 140DZ at 8 - 8,500. Would a Mezjlik 18x8 put it in the preferred range? Its running on Wildcat 30% Heli fuel. Since the manual shows a practical range of 7,800 to 9,000, what happens over 9,000 - do the valves float?

Thanks