age of car not the problem ..lots of paper work
depends on which state you register it
some US states much stricter on emissions before registration
link for information
State Emissions Standards and Testing - FindLaw
link for importing a car into the USA
- Clean the Undercarriage. ...
- Vehicle Contents. ...
- Prohibited Imports. ...
- Gas-Guzzlers. ...
- EPA/Air Emissions:
- DOT/National Highway Traffic Safety Administration (NHTSA):
- U.S Customs: