HAVE YOU BUMPED IT TO SEE WHAT IT SOUNDS LIKE? YOU DON'T NORMALLY HAVE TO ADJUST EM MUCH. TRY TO LINE IT UP STRAIGHT WITH THE REST OF THE ENGINE. YOU CAN CUT THE SHIMS IN HALF AND START BY ADDING A LITTLE BIT TO THE BOLT CLOSEST TO THE ENGINE. THAT BACKS THE STARTER AWAY FROM THE GEAR. IF YOUR USING A GM REBUILT STARTER, THAT IS USUALLY THE WAY YOU HAVE TO SHIM IT BECAUSE THE REFACE THEM SOMETIMES TO SQUARE EM BACK UP WHICH IN TURNS PUTS THE STARTER GEAR TO CLOSE TO THE RING GEAR.