I noticed that Jetdriven mentioned that he had his timing changed from 20 deg. BTDC to 25 deg. with better performance noted, especially LOP.  The below info from the type certificate for the I0-360 A1A ends with the note that 25 deg. is spec, with 20 deg optional.  Pretty weird, huh?  So, how is your timing set, why, and what effect do you see?  Anyone else changed timing and has before and after?               1E10 Page 2 of 18  Model    (cont'd) IO-360-A1A, -A1B, -A1B6, -A1B