Hi there, the MK3 crank is 3mm wider between the faces of the bbearing and thus the MK3 cases are 3mm wider, you can fit a earlier crank into MK3cases but must shim behing inner races (1.5 mm thick each side).Don't ask why I know it, of course the late crank are different on the drive , as the shaft is longer, and the crank bolts are stronger, without mentionning the notch on the timing side cheek which could be used to align through the case, with the plug (for TDC or 28°?). The frog