Posted for "Jack Cowell" <jcowell@nyc.rr.com>:

With all due respsect to your knowledgeable mechanic, quite a few turbo
motors perform quite well for long periods of time when they're operated
LOP. For example, there are almost 1200 hours on the Continental turbo 550
in my IVP and it is always cruised at least 60 lean of peak at 29-30 inches
and 2500rpm.  Climb is also always done full rich and at around 30-31 inches
(depending on the day). Compression readings are all in the low 70s with one
sneaking into the mid-60s.  Maybe I'm lucky, but them's the facts.  Jack
Cowell