[macaman]

I fly a '68 T337C between Salt Lake and California at 14 and 15,000 feet and usually get 165 knots (195 mph) True Airspeed at 65% power. The book shows 20 gph for these power settings but I find I need 23-25 gph to get 50-100 degrees rich of peak.

The book shows a possible true airspeed of 220 mph (190 knots) at 25,000 feet at 22.7 gph. The numbers may be easier for the later Turbo models with more than the 210 hp engines I have but you'll still be in the flight levels cruising at 75% power to get that number.

I really enjoy having the turbos with density altitudes that can top 10,000 feet at my 4,500 foot elevation runway in the mountains, especially to out climb the Sierra Nevadas but if I were flying in lower terrain most of the time I'd definitely lean toward the normally aspirated model. We have a Hawk XP (210 hp Cessna 172) that does just fine on VFR days cruising up to 12,000 feet where it sips 7-8 gph for 110 knots or high speed cruise of 130 knots on 12 gph at 8,000'.

I guess the big thing is that you can't just set it and forget it with power on the Turbo models, you become a true manager of the engines and on working with ATC to be able to cool the engines slowly on approach but if done correctly, the turbos will treat you right.

Good luck and if you would like, I can e-mail you the performance section of my owners manual. Just private message me your e-mail address to see them.