[David Dixon]

1550 hrs amazing. I'd still check the corrosion factor. The airframe is strong enough I'd think, I've never heard of one bending, though you do have to be careful of something they call 'Boom Bounce" which can weaken the main spar, but this is in any Skymaster not just the 336. Boom bounce is caused by the controls not adjusted to correct tension and the product of this is an oscillation rocking feeling when the plane is trimmed.
Fuel burn, say at 3500 to 4500 ft I plan for 80 lts per hour on average and this takes in account taxi. You'll have to work that out in gallons for you, but I find on my fuel flow that when I lean it out, it shows on average just under 11 gallons per hour per engine. anything less than that the egt rises above the accepted.
My speed with the rear cowl open is about 130 knt mph but that increases when I have my wheel farings on which they are not at the moment. My mate in Washington State says he has 10 knts on me.
No I haven't had to balance the rear fan, never thought of it. I don't get vibrations, but it all helps I suppose.
The rear head temp also runs hotter I'm not in front of my instruments at the moment, but I'd guess at about close to 350 for the front head and closer to 400 on the rear on a hot day. Oil pressure around 50.
Re Oil temps, under 200 on a cool day for the front and over 200 on the rear. For me, anything out of the red on the rear oil is good at the moment, I'm sure I have a faulty wire between the transducer and the guage as I've replace EVERYTHING except that.
It's really annoying. My plane is fairly highly maintained and I've just had it painted. New pic to be posted when I get the wheel fairings on.
Anything else feel free to ask.
David