The '573 is a transparent latch. It doesn't work the way you guys are describing it. Here's a quote from the datasheet:
"The “573” consists of eight D-type
transparent latches with 3-state true
outputs. When LE is HIGH, data at
the Dn inputs enter the latches. In this
condition the latches are transparent,
i.e. a latch output will change state
each time its corresponding D-input
changes.
When LE is LOW the latches store the
information that was present at the
D-inputs a set-up time preceding the
HIGH-to-LOW transition of LE."
In other words, when LE is high, each D input passes directly to its corresponding Q output. When LE transitions low, all Q outputs hold the logic levels that were present at the time of that transition, and remain latched until LE goes high again, at which time they resume tracking their inputs.
You can use a quad NOR or NAND latch
(CD4043 or CD4044).