Here you can see the inverted seventh chords.
The numbers come from the intervals above the bottom note in the chord (and upon its inversion). The long forms are: 753, 653, 643, 642 - for "root position", "first inversion", "second inversion" and "third inversion", respectively.
From the diagram above, you can see where the numbers come from (count your lines and spaces to match up those intervals. You can do it! :P )
Anyway, the abbreviations for each are highlighted. So your 4-3 chord is just a second inversion chord. These inverted chords tell you only one thing though: what your lowest pitch is going to be.
So a root position has the ROOT on the bottom
A first inversion has the 3rd on the bottom
The 2nd inversion has the 5th on the bottom
And the 3rd inversion has the 7th on the bottom. (3rd inversion can be called "4-2" or just "2" in some sources)
Triads (chords with 3 notes) work the same way
Your root position then is 5-3, first is 6-3, and 2nd is 6-4.
The abbreviated versions are: (nothing), 6, and (still) 6-4.
I hope you can figure that out on your own. Try drawing it.