Posted for Walter Atkinson <walter@advancedpilot.com>:

 A timing of 28 degrees BEFORE top dead center is more advanced than a timing
of 24 degrees BEFORE top dead center.
 
 Advancing timing makes the EGT lower and CHT higher.  Retarding the timing
makes the EGT higher and the CHT lower.
 
 Advanced timing, therefore, results in higher ICPs and decreased longevity.
 
 At the power settings we generally use, moderate changes in timing have
little effect on HP.
 
 Walter