Difference between 2 Saginaw PS pumps

All. Looks like my replacement pump is similar to the one on the left as you cannot see the low pressure connection. The middle pump low pressure connection is visible and would work so it looks like the "square" saginaw pumps come in at least two configurations. The right pic is like my original. Use an original replacement or square pump with low pressure connection up high.
This pump mounting information for small block!!!! Big block may differ and I don't recognize those brackets so they may be for BB.
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