After much searching I emailed CARB with my phone number, just received a call and was told:

The engine must be out of a road going car that was sold in the US in that year or newer. (or equivalent in that the engine from a 1981 XXX might be functionally identical to the engine in a 1982 XXX, but if there is any way they can tell then no). They go by model years.

They will verify that all emissions equipment (only EGR that I know of on the diesel, maybe evap canister??) for the diesel engine car is present.

They WILL NOT smog check (tailpipe test) the engine, just a visual check to see that the engine was swapped.

Once this is done the car will be smog exempt like all other diesels.

Car should have all original equipment components in place air filter etc etc.