Thanks for the information. I'm already leaning on the ground quite
aggesively as i've been told the O-540 plugs foul really easily with
the very rich mixture the Aztec is set-up for full rich.

One last question (sorry for the ignorance) but how do I know that that
particular EGT is the highest reading. i.e. is it taken off an
individual exhaust outlet or further down the exhaust (i.e.
common/averaged reading). Just wondering what the case is if the EGT is
out, and you lean to an incorrect EGT figure?

Dean