An entire web page for prospective 337 buyers exists in the "other" website at
www.skymaster.org.uk/purchase.asp which deals with many of these issues. The "hot rear engine" story is just that, a story. As others have said above, the rear engine runs marginally hotter than the front but well within normal bounds and has no impact on TBO. And, yes, if you are in Miami (as I am) and have a long delay in taxiing (which typically faces downwind) the rear engine can overheat. This happens, like, never, so it's not an issue, but if it were, that's what the temp guages are for, and you take corrective measures (like shutting off the rear engine while you wait).
Ernie
Hybrid Mode
