Posted for "Lewis III, Charles S." <CSLEWIS@stoel.com>:

 Walter:
 
 You said:
 
 <1)  It's NA, not TC'd.>
 
 <2)  Did you mean a TCM IO-550N  or a Lyc IO-540???>
 
 Right -- naturally aspirated.  I thought that was what Rob originally
referred to when he said "but that's for 8.5:1 heads, and I think the TSIO is
7.5:1... (with everyone now running 10:1 NA)"
 
 My engine is a TCM IO-550.
 
 Carl