Looking at a 67 Twin Comanche. Has O-360 engines... near TBO. Is it possible to replace these with 200 hp IO0360s - without breaking the bank with STCs and other expensive hold ups?
Coaching would be appreciated!

I would not even think about it. You can buy an IO-470 Baron that is cherry for under $100k and it will be faster and more fuel efficient than the TC. You will spend $80k+ just switching out the engines. Buy the Baron.

Dan, I thought the Twinkie had IO320s which are extremely economical and darned near bulletproof and, Todd, one owner on the Piperforum, who's opinions I respect a lot, has stated she gets TAS of 160 at 14gph at 10,500'. Can the Baron match that for efficiency? If so, I'd for sure have a look.

But then you have the whole Lycoming:Continental TBO comparison and the undeniable fact that there's a lot more room for big people like me in the Twinkie. Tough to say.

160 knots on 14 GPH would be about right at 10500 for either airplane, but it may be 16 in the Baron. The Baron will do 180 knots on 22 GPH.

The 470s are pretty bullet proof, definitely not as good as the 320 Lycs, but the Baron will destroy the TC in climb, useful load, handling, etc.

The TC is an efficient little plane, but it isn't much of a twin IMO. I have seen some pretty darn nice 470 Barons for $80k or less.

Instead of swapping engines, it would be much easier to find a twin comanche with the larger engines. They are rare though. I do not think the STC for the bigger engines is sold any more.

The Twin Comanche originally came with IO320 160hp engines. These airplanes are highly efficient with a nice wide cabin. The STC for IO360 engines is called the Miller Conversion. I don't think that is available any longer. I owned a PA39 for 10 yrs. 172kts @ 7000ft burning 17.5 gph.

Robert

thanks for the help guys.
It seems I'm hauling four guys alot now, and the TC just looks very efficient.
I appreciate the help

You are going to spend 25-35k on engine overhauls as it stands. You might be happier if you take that money, and what you would spend overhauling a high engine time Twinkie, and spend it on a good TravelAir, C Commanche, Turbo Commanche, or even a Seneca II or B-55 Baron if your wallet or mission supports it, you may be a bit happier. Before you do anything browse through the Cheap Son of a Beech site.

Years ago I debated between the Twinkie and the TravelAir and went with the TravelAir because of the cabin, O-360s, and 5 seats, which I only used a few times. At the time there were no Turbo Twin Comanches on the market and the Barons and Seneca IIs were too rich for my budget and mission.

The 1960 TravelAir won out given the options on what was available on the market at that time. It was in they heyday of the .com boom and people had $$ and this was going to be a trainer so I didn't need a TSIO. On the TravelAir it was about 2GPH more to get 160-165KTAS at "FL100/110". The Twinkie was about 12-14 GPH and we were about 16GPH. We also chewed through a few gallons more getting to altitude near gross. The TravelAir was just a smidge roomier but the Twinkie had brakes on the R side; most TravelAirs don't.

The TravelAir was more forgiving on landings for my students.

Most parts were easy to obtain for either bird. The TravelAir seemed easier to maintain than the Seneca II at my friend and competitor across the ramp. I flew their bird when my TravelAir was busy with students. They used the Seneca II for training but were focused on their 135 certificate before they sold their business and the owner headed to the airlines.

...guess I am just biased towards Beech.