? about swapping engines

[accordboi21]

wussup
i was thinking of doing an engine swap and i heard that if i wanted it ta be all legal i gotta take it ta state ref and show papers. then they'd inspect everything and smog check it there. is this true?

[Michael]

Let's say I get a car to "pass" smog, so I go to the DMV with the certificate. Is there anything they can do that will prevent me from registering the car? I remember them checking the VIN number and something else under the hood, what is that? Thanks for any info, I'm in CA.