[Synchro909]

The engine number on a B engine is not on the pad on the side of the block. It is on a pad on the flywheel housing just above the starter. To use an A gearbox on a B engine, the flywheel housing is changed for one from an A engine and the sheet metal part of the housing removed from the back of the sump. The B number is lost. All that is left is the blank pad on the engine. That might cause some head scratching when it comes time to register a car with such a set up in it.