Does it pass or what do you have to do to get it to pass?

 

It will in Texas where I'm registering mine. It depends on your state/county laws.

 

Generally, the emissions components have to match the car the engine came out of. Pretty much any state is going to require the engine be at least as new as the chassis it's going into. Some states or areas may allow you to get away with missing some of the components. Things like a fuel pressure regulator under the hood are a no-no in California, but in backwoods Indiana the inspectors probably wouldn't even know what it was.

Depending on the motor you install, you will likely have better emissions results than with the rotary. The LS1, for example, is one of the cleanest-burning stock V8 engines ever designed. Once you start modifying it, the results go down, but stock for stock it's MUCh cleaner than a rotary.

 

Like CTJ said, as long as the original emissions equipment is still intact, you will usually pass sniffer tests.