How can I tell the difference between a early and late trans

[Chunk]

I'd like to get a few spare parts "just in case",but what are the physical differences? Different gear ratios? fill plugs in a different spot? Do they hold a different amount of oil? Do the top covers interchange?etc,etc. Pictures of both side of the trannys would be helpful. Thanks,Chunk

[rixm37]

The shift tower is different skinnier. and looking at the back the old style has a plate with an arm on it that extends across the back at the 9 o'clock position. The plate on the back is the quickest way to tell.