How Do You Replace Obsolete 74 Series Glue Logic?

The answer

You take the original design, rebuild it inside a newer programmable logic device, then build and test the parts to prove they behave like the originals. Because the old 74 series logic was simple, one programmable device can do the job of around four of the old parts.

The replacement is only accepted once it has been built and tested against what the originals were supposed to do. Read the full explanation.