I have been able to consistantly get 140 KTAS at @ 90% TQ over the last year. This has been from SL up to 13,500 and very consistant at usual T/O weights fo 5700-6000 on ferry flights. Usually 65-70% will give you a cruise of 125KIAS with a fuel burn of 500pph, 85-90% will give you another 10+ KIAS with a 100 PPH burn rate increase.
Currently you are limited to 100 KIAS above 6250 pounds, but that will go away soon. In the EXP program we get 6500 pound Vh better than 135 KIAS at DAs below 5000. We were given a limit of 126 KTAS for a demonstration program, and with 6500 pounds and external hoist installed we achieved that with mid-70s on TQ.
This info is with 207E engines installed. Also of intrest, 100% TQ is available up to above 8,000 ft DA before hitting any yellow EGT.
Cheers
Mark