Are your saying you wanna take a new motor, put it in a old truck, leave all the emission controlls off, and pass inspection?
Law says (or at least trys to say) that the emissions standards for a vehicle is based off the year of the motor in the vehicle.
But that doesn't ever get "checked". I have a '86 sbc 350 in my '63 scout. exahust is headers to glasspacks, thats it, no cats. Carb is a non-emissions Holley. When I get it inspected the guys looks under the hood and doesn't even think twice about it because the title/insurance says 1963 scout.
Main point: Pretty much doesn't matter what modifications the vehicle has, the inspection requirments (in practice) are set by the year of the vehicle. ( seat belts, hazzards, emissions, etc.)