By the way, how did your [Soob] installation go? Any stories to share?

It was a major headache. The engine mounting was especially
knotty, since all the acceptable mount points are at the front (former
rear) of the engine, and there were 17 separate tubes welded together
when it was done. The average Lyc has 9. The redrive (RAF) put the prop
shaft centerline above the engine, so the engine had to sit low in the
cowling (a Glastar O-240 fit, modified) and there was no room for
mufflers of any size and effectiveness. Went through 7 iterations of
those, trying to get it quiet enough that we couldn't hear it flying 8
miles away. Cooling, on the other hand, came off well: I mounted the
radiator (full-sized Subaru) on a plenum, angled from the firewall so
that the only exit for air entering the cowl was through the rad. The
top of the rad was against the firewall, the bottom 7 or 8 inches out
from the lower edge. A lip on the cowl made sure of a low-pressure zone
there. That rad had to fit behind the engine and mount. The cooling
system has a thermostat on the inlet side of the engine, rather than
the outlet as in North American vehicles, and relied on return coolant
temp from the heater core to tell it when to open. So the core had to
have full flow all the time, making the cabin warm, or it had to have
bypass flow, which I did by making a four-ported shaft/poppet valve
controlled by a panel cable. Not simple at all.
The carb had been modified for manual mixture control, with an
EGT in the system, and a burned valve resulted when the mixture was set
too lean. I found that the valve (four per cylinder) was about the size
of a lawnmover engine valve, very thin and with a slender stem, and
would burn very easily compared to a Lyc's robust valve. Subaru could
get away with that using computerized fuel injection, which would make
sure the mixture never got that lean, but the FI system weighed 40
pounds, so had been ditched in favour of a carb. Since leaning was now
limited, the thing wasn't all that economical. Further, the engine had
to be cruised around 4700 RPM while redline was 5600, so cruise speed
suffered. The engine life would be low indeed if it was cruised close
to redline as we do with Lycs (Redline 2700, say, for an O-320, with
cruise at 2500 or so). Temperatures and fuel burn weren't good at high
RPMs.
I maintain full-time six Lycs, From O-235 to O-540, in a
flight-training operation (just about the worst environment for an
engine) and we have VERY few problems.

Dan