TAC = Thermostatic Air Cleaner. It's just an air cleaner with an air riser attached to the left exhaust manifold, and a vacuum operated temperature valve to control the temperature of the air the engine receives. If you have headers, you should be able to buy a heat riser that clamps on to one of your tubes.

Yup, cats were mandatory in California, my truck(s) have them.

Now for the air pump tubes on a 460, the tubes were routed to holes in the back of the cylinder heads. Very hard to get to with the engine in the truck. If your engine does not have them, or if your heads don't have the holes to accept the air tubes, you may have an issue.

Got your PM, I'll send you the vacuum diagram tonight, when I get home.

Hope this helps.