My experience has been a bit different than that of T-Wal; although the piston and rod assemblies are matched, the MB inline crankshafts are not neutral in themselves (the V8s are). As a consequence, weight is carried externally, both on the front hub for the torsional balancer, and on the flywheel. Hence the replacement flywheel, either manual or automatic, must be matched to the imbalance of the original.