Truck bell. There is an Iron one, with side mounts, takes a starter that bolts to the bell, and has the conventional Muncie/Saginaw pattern. As far as I remember, 168-tooth flywheel. 1962-67-ish. 3815891, I think.
Here are photos of the ‘55-57 passenger car bell, notice the proximity of the fork pivot to the register diameter in the second photo. These two photos are of a pickup truck bell as mentioned by @gimpyshotrods . He called out a casting number (or is that a part number?) but they will be found with a variety of casting numbers. The important thing to look for in a pickup bell like this is the space from the edge of the fork pivot to the register diameter, some pickup bells will look the same but have the larger register for the heavy duty truck four speed.
So it's literally the bell that came with this engine? Hahahahaha... I told you the beer coaster was small! Brilliant. Thanks men.