Regarding the Toyota engine swap you are considering: Yes, you can do it. However, while installing the new engine (in another pickup truck, Toyota 4Runner, or Toyota with originally a V6 engine), you will need to install all the emission components for that engine as well. In other words, you'll need to swap not only the engine core but all the emission components as well, from the engine control computer to the exhaust system.
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 all is well they will issue you a BAR label which will be placed somewhere on your vehicles chassis which will be an indication that the vehicle is California legal.
In this case we recommend you speak directly with a State Smog Check Referee before beginning any work, just to get the fine details and up-to-date information. You can contact the referee by calling (800)622-7733.
