We no longer will process an engine to be SMOG compliant.
Current laws and regulations are constantly changing. It may be possible to process an engine to meet TODAY'S requirements, but may not be compliant by the time your project is completed.
SMOG applies in many states on vehicles newer than 1976.
I never recommend an engine swap that is not as 50 state complainant as possible. You may not have current SMOG requirements in your location but that may change, or you may want to sell the vehicle later. This will significantly limit your sales market and value of the vehicle.
The biggest stumbling block to meet the strictest SMOG requirements is replicating the factory EVAP system. The EVAP System evacuates and digests the fumes from the gas tank. It comprises many components and has to be calibrated in the tune to match fuel tank capacity.
IMO EVAP is NOT part of the engine emissions and is part of the original vehicle chassis, but unfortunately GM utilizes the engine ECM to monitor this system and it is listed in the Emissions Readiness Tests section when the vehicle is scanned for SMOG. In the past it was acceptable to turn the EVAP tests off but now several states have utilized a new procedure to validate that the "tests" are active and working. They want you to arrive for your test with the "Drive Cycle" completed and all tests reporting "Complete". Then they clear the DTC's and want to see the readiness test report "Incomplete" and turn red. This new procedure has been procured by some aftermarket engine swaps running dual ECM's, one for the engine, and one for the chassis. This is common with import swaps and is often associated with a swap that is NOT emissions legal.
IMO this is very unfortunately and I feel your frustration. Many people have vehicles in the 1976-Current era that they would like to "swap" a modern, clean burning, lower emissions engine into, but the Federal Government is making it practically impossible. Many of these vehicles have sentimental value, were your fathers, or mothers and you want to keep them and I understand that. But unless local DMV's would recognize that on these particular GM Vortec engines the EVAP is NOT part of the ENGINE emissions there is not much we can do. The EVAP portion of the tune is embedded deep in the binary code and can not be changed by any means I know of or have researched. The complete emissions section can be eliminated by a segment swap but it also removes wanted emissions like Catalyst, Oxygen Sensors, etc.
It is interesting to note that even GM's current "Connect & Cruise" and "E-Rod" packages do NOT list EVAP in the emissions section when scanning for SMOG - It is reported as N/A, as seen by other non existent systems in the image above.
This website has a good State by State listing of current SMOG regulations. Click link below.