YEP ISLAND RACER IS CORRECT ON THIS ONE ABOUT THE 2.3 TIMING MARKS , THEY ARE ON THE LOWER PLASTIC CVR IN THE EXACT SAME SPOT AS THE 2.6 , IN FACT THE CVRS ARE THE SAME PT NO, HOWEVER THE PULLEY /DAMPNER ASSY IS COMPLETELY DIFF, THE 2.6 USES THE DAMPNER THAT SLIDE ONTO THE CRANKSHAFT NOSE AND THE CENTER BOLT GOES IN TO HOLD IT ON , AND THE ACCESSORY DRIVE PULLEY BOLTS ON WITH 4 BOLTS , THE 2.3 HAS A HUB THAT BOLTS ON WITH THE SAME CENTER BOLT BUT THE ACCESSORY DRIVE PULLEY/PULLEYS (2) BOLT ON WITH 8 6 MM BOLTS AND THEY CANNOT BE INTERCHANGED BECAUSE OF THE TIMING GEAR SPACING .. JERRY