Posted for Sky2high@aol.com:

 I believe the original question was about running a Lyc O-320 with  EGTs 50F
 Rich of Peak (ROP).  Later comments considered using  CHTs as some sort of
 indicator.  Others talked about different  Manufacturers' recommendations.  
 Returning to Lyc data, included and  attached is a page from the Lyc 320
Operator's
 Manual:
 
 Note that the flattest part of the top of the % power  available curve exists
 with EGTs between 100F ROP and 150F ROP.   Please note that the peak CHT is a
 50 ROP and from GAMI data, that is probably  the worst place to run the
 engine (assuming CHT has any meaning).
 
 Note that the best economy is in the EGT range of about 70F LOP to 10F  LOP.
 
 
 I run my IO 320 either at about 110F ROP or about 50F LOP,depending on  
 whether I wish to go fast or not.
 
 I don't see any reason to run the engine outside the Manufacturer  
 representation for best power or best economy and in agreement with GAMI  
 recommendations.
 
   
 
 Scott Krueger  AKA Grayhawk
 Lancair N92EX IO320 SB 89/96
 Aurora, IL (KARR)
 
 Pilot  not TSO'd, Certificated score only >  70%.