Has Anyone Sorted Out the "LA" Cylinder Block Motor Mount Tab Variations?

Is there an online reference to explain all the ins and outs of Mopar LA block motor mounting tabs? I have three motors with three different arrangements! There must be a bunch of different factory brackets out there, too.

The 318 block I am looking at (casting date 12/04/79) has:
On driver side 2 tabs in front and 2 tabs behind for a total of 4 tabs.
On passenger side 2 tabs in front and 1 tab behind (upper location) for a total of 3 tabs.

The 340 block I am looking at (casting date 09/28/71) has
On driver side 2 tabs in front and 1 tab behind (upper location) for a total of 3 tabs.
On passenger side 2 tabs in front and 1 tab behind (upper location) for a total of 3 tabs.

The 273 block I am looking at (installed in a '65 Signet convertible) has:
On driver side 2 tabs in front and 1 tab behind (upper location) for a total of 3 tabs.
On passenger side 1 tab in front (upper location) and 2 tabs behind for a total of 3 tabs.

I can't see the 273 driver side bracket very well, I am fairly sure it only has 3 tabs total.