I HAD THE SAME PROBLOME MY LIFTERS WOULD TAP WHEN WARM OR HOT THATS WHAT IT SOUNDED LIKE I FIGERED OUT THE PROBLOME AFTER 2 SETS OF NEW LIFTERS AND HEADS AND ROCKER ARMS LATER WHAT I FOUND IS THAT THE NEW PARTS I GOT HAD THE WRONG JET VALVE ADJUSTER BOLT IN IT. THAY WHERE TO LONG AND HITTING THE VALVE COVER WHEN THIS HAPPEND IT CAUSED THE INTAKE ROCKER ARMS NOT TO HAVE THE FULL UPWARD TRAVELL WHICH CAUSED THE LIFTER TO CALLAPSE DUE TO THE LIFTER HAVEING SHORT UPWARD STROKE AND NOT EXSTENDING OUT AS FAR AS THE LIFTER SUPOSED TO GO. AND I BURNED A COUPLE OF JET VALVES TOO AND IT DID NOT SOUND LIKE IT WAS A CLERANCE PROBLOME BETWEEN THE VALVE COVER.I FOUND A WITTNESS MARK ON THE INSIDE OF THE VALVE COVER IN THE BAFFLE I ALLMOST MISTAKED IT AS A SPOT WELD.I REPLACED THOSE ADJUSTER SCREWS ON THE JET VALVES AND THE OLD ONES WHERE A LOT LONGER ABOUT 3MM.AFTER THE CORRECT ONES WERE INSTALLED NO MORE NOISE AND RAN GOOD.AND NO TSBS FOUND ON SUCH A PROBLOME 2.6 G54B