As above.... FWIW, the bolt is what clamps the damper to the crank for the case of a SBM. The purpose is make sure all of the higher frequency vibrations are coupled into the damper so it can do its job. With the 135 ft-lbs torque on a 3/4" thread bolt, the clamping force is somewhere in the range of the 10,000-12,000 lbs. The interference fit can't come anywhere near to that 'locking' force and is not reliable anyway for higher vibration levels, due to variations in the fit. (It is obviously adequate for the /6.)