The NOS B-8510 water pump housing shown above was used on 1932 Model B Ford vehicles which had the radiator core oriented straight upright. 1933 Model 40/46 vehicles had the radiator core tipped back on an angle.
The Model B water pump is longer than the similar 1933-34 Model 40 and Model 46 water pump assembly 46-8505 shown below.
The Model 46 water pump was used on 4-cylinder cars and commercial vehicles which had the radiator core laid back at an angle. The Model 40/46 water pump housing and shaft was similar to the Model B, but much shorter. The two grease fittings very nearly touch each other on those water pumps.