How many different bellhousings were used on the 49-53 flatheads? Are the 3sp and 4sp different? How would one tell the differnce? I would assume the truck is different from the car...correct? How does one tell the differnce between a truck and car?

Thanks.

 

Briefly, and probably with some missing info - the truck uses a 2 piece cast iron bell.
Mercury cars also use a 2 pc bell, but it is stamped steel (at least the front half).
The Ford cars used a 1 pc bell of stamped steel.

Where it gets goofy with trucks and maybe the mercs, some transmissions have the back half of the bell cast as part of the trans housing.

The truck 3 spd HD has a bolt-on half bell much like later trans. I think this is true of the 4 spds also, but I'm not positive.

The rings you see for sale that are used with adapters for modern trans are the truck and merc front half bells. The adapter bolts to the back of it for whatever transmission you choose to use.