Eric -

You said

" ........ as is the arrangement of the downdraft cooled TSIO-550N. The
factory recommended engine for the Lancair IV (TSIO-550N) ........"

Admittedly it's a minor point but there is no such thing as a TSIO-550-N.
TCM makes the TSIO-550-A, -B, -C, and -E.
Lancair recommends the -E engine for the Lancair IV.


Ted Stanley