PHIL WHEN YOU REPLACED YOUR CYL HEAD DID YOU HAPPEN TO NOTICE THE COMBUSTION CHAMBER FOR THE NEW ONE, DID IT LOOK EXACTLY LIKE THE OLD ONE , OR BY CHANCE DID IT HAVE KIDNEY BEAN SHAPE OR A TWIST TO THE COMBUSTION CHAMBER, IF YOU HAVE A 93 OR LATER CYCL HEAD, YOU WILL HAVE PINGING UNLESS YOU SET THE TIMING AT AROUND 6 DEGREES , THAT HEAD ON THE OLD SYLE BLOCK WILL RAISE YOUR COMP TO ABOUT 9.0 OR BETTER, AND YOU WILL HAVE TO KEEP THE TIMING BACKED OFF A BIT ,, 93-94 AND LATER 2.6,S USED A MUCH DEEPER RECESS ON THE PISTON TOP THAN THE EarlIer VERSION, IT MAKES A GOOD BIT MORE PWR BUT IT DOES HAVE A TENDENCY TO PING WITH OUT PLAYING WITH IT A BIT , I HAVE NEVER SEEN ANY OF THESE ENG WITH ENOUGH CARBON BUILD UP TO PING , BUT YOU MIGHT GIVE RANDIS SUGGESTION A TRY , IT WON,T HURT ANYTHING , DO LIKE HE SAYS AND DON,T GIVE IT TO MUCH TOO DRINK AT ONCE