This pic shows a typical 1932 Model B Ford B-6395 flywheel housing. This housing was used in 1932 on all cars and trucks. Note the machined pads on the side for the rear engine torque rod bracket mounting.
The pic above is the 1933-34 Model 40 and Model 46 Ford flywheel housing 46-6395. Note that the machined pad is gone and that a hole is added for mounting the engine torque rods directly to the housing, similar to the flathead V8 engines.
This housing was used in 1933 and 1934 on the four cylinder Model 40/46 cars and light commercial vehicles using torque steady rods.
The addition and position of this torque rod hole also required a change in the transmission case. The mounting flange of the 1933-34 four cylinder transmission case has clearance notches in it to clear the torque steady rods.
The 1933-34 transmission case can be used on 1932 Model B flywheel housings without modifications, but the 1932 Model B transmission case (without the notch) cannot be used on the 1933-34 Model 40/46 vehicles without adding a clearance notch to the flange.
Shown above is a direct comparison of the flywheel housing differences. Model 40/46 flywheel housing on top, Model B on the bottom. Both housings are cast and machined grey iron.
US and Canadian Model B and BB, and British (1932 only) Model AB, ABF, B, and BF serial numbers were stamped on an as-cast pad on the top of the flywheel housing, above the starter as shown in the pic below. The engine block pad was left unstamped and as-cast.
The pic above shows the typical US and Canadian Model B engine number location on top of the Model B or Model 46 flywheel housing, above the starting motor. Note that the number reads from the front of the engine in this example. Others read from the rear.