[rotorwrench]

The early motors require the early flywheel due to starter placement in the pan/bell. 8BA family is different starter placement but the crankshaft bolt up will work for either flywheel in either block. You can use any 59 series pan on the 99A or later pre-war 239 blocks since they are basicaly the same. A relieved block was probably in a truck. I don't think they relieved the Merc blocks but who knows!