What type of emissions testing applies if a vehicle’s engine is replaced with another of the same fuel type?

When a vehicle's engine is replaced with another engine of the same fuel type, the applicable emissions testing procedure is determined by the chassis' model year. This is based on regulations that take into account the environment and technology standards established for that specific year. The chassis serves as a primary reference because it dictates the overall emissions requirements based on when the vehicle was manufactured.

In contrast, the procedure associated with the old engine's model year would not apply, as the focus shifts to the vehicle's current configuration. While previous emissions standards may inform some practices, they are not relevant in this context where the chassis dictates compliance. Specifying that the vehicle is not subject to any testing is incorrect, as all vehicles must adhere to current emissions requirements based on the chassis and any modifications made. Thus, using the chassis' model year for emissions testing ensures that the vehicle meets necessary environmental regulations reflective of its current setup.