What is the difference between these two wiper motors?

Also, what GM A bodies do they each fit?

 

The difference is one uses a bell crank arrangement to perform it's operation. It uses a short bar about 2.5-3 inches long with a slot in it to connect to the wiper transmission assembly. This is the old school motor.
The lower one uses the offset of the center attachment to perform the movement like a bell crank would. I'm only guessing but I think that is a newer version, possibly a G body.

 

IMO I don't think the photo is clear enough to define the difference of the two.... Unless you are explicitly referring to the motor shaft.... from the photo, the difference only appears to be cosmetic.... I don't think the motor shaft functions any differently in the lower view then it does in the upper, unless for some reason you think it might function in an orbital motion... they both appear to have flat spots on the shafts to accommodate the bell crank that attaches to the wiper transmission....

 

Cruzn, that center shaft is clearly offset in that lower motor

 

IMO, and from what I can see in the photo, the two shafts are located in the same position on each of the motors.... What makes it appear offset is the location the hole was machined relative to the actual housing.... The area that looks like a "C" is what is offset from the center of the housing.... Now if that area is actually separate from the housing and rotates with the shaft and another item actually seats into the open area of the "C", then I would agree that it will function in an orbital motion... Again, JMO...

MY442 should be able to tell how the shaft actually rotates....

 

The number cast in the housing, 4939300, is the casting number for the body of the wiper motor and not the part number. From what I can tell it is the casting for the 68-72 housings. The part number would have been on a tag on the housing covering the electric motor. It's obviously not a G Body wiper motor like I thought earlier. Why the center post is different I can't answer.
Apparently also used on Corvettes.