HCMOS drivers impedance table
TI do some good app notes on their logic families, it's just a matter of finding the right one :-)
I have one here on my computer called "Designing with Logic - SDYA009C" containing the table shown below. It's a little old now (1997) but I'm pretty sure there will be a similar app note for the newer chips. Here is a TI page with tons of logic related documents.
The HCMOS design guide and Input/Output characteristics might be of use.