Originally Posted by eastcoastbumps
Like Jack said, I've done two LS1 RX7's. They're a blast. I just picked up an RX8 for another swap. '95 and older (pre-OBD2) are emissions exempt in MA. Its just a safety inspection.
If you have a '96 or newer chassis, you must maintain OBD2 functions and pass the plug in test. You're also limited to using an engine that is the same year or newer than the chassis. They will do a visual check for cats as well, just like any other emissions test.
Just a quick search I did, you might want to check with the MA dmv or sec of state (or whatever you guys call it), as this thread is 3 years old, but probably still accurate as he had experience doing swaps in MA.