The exact emissions equipment varied depending on the engine and whether or not the car was originally sold for use in California (not necessarily where it was built). For example, my 77 was built in CA but went to a dealership in Oregon (according to the build sheet I found under the back seat) so it just had the federal/49-state emissions equipment.
Page 27 of the 1977 Nova info pack from the GM Heritage Center (http://www.gmheritagecenter.com/gm-heritage-archive/vehicle-information-kits.html
) gives a complete list of all the emissions equipment as follows:
(positive crankcase ventilation) was used on all engines.
(exhaust gas recirculation) was used on all engines.
(carburetor hot air) was used on all engines (this is the air cleaner with a tube leading down to a heat stove on the exhaust manifold).
(manifold air injection) aka "smog pump" was CA only for the L6 & 305. 350's got the smog pump on both CA and "high altitude" 49-state emissions packages.
(fuel evaporation control) was used on all engines (this is the charcoal vapor canister setup)
(controlled combustion system) was used on all engines except in CA. This is basically carb & ignition tuning to meet the 49-state emissions requirements.
(under floor converter) aka catalytic converter was used on all engines.
(early fuel evaporation) was used on all engines (this is the vacuum actuated valve on the exhaust manifold outlet (RH side on V8).
(monolith manifold converter) was used on L6 in CA only. I think this was something to do with the way the smog pump injected air into the manifold/converter on these engines that was a little different than the V8 setup.