Engine swaps are legal. While installing the new engine you will need to install all the emission components for the particular engine as well. The emission requirements for your vehicle will follow the engine make and year, not the chassis into which it is installed.
After the swap is complete, the vehicle will have to be inspected by a California State Referee. The Referee will ensure that the job was done properly and that the new engine does not pollute. If the engine swap was done properly they will issue you a BAR label which will be placed on your vehicle's chassis indicating that the vehicle is California emissions legal.
posted by SmogTips Support