mutantfrog

@JonSnow83 I own a Euro 911SC. Like your car, it used to have a cat. The car is currently registered in Illinois, but I am thinking of moving to Colorado. How did you end up registering your car given CO's emissions rules? Feel free to point me to a different thread.

jcmolina17

what shop? I have the same issue now that my 1977 corvette did not pass emissions because no catalytic converter

raspritz

A lot of the info in this old thread is obsolete and incorrect given current laws. Colorado law now restricts new collector plates to 1975 MY and earlier cars, which never require emissions testing. The plates are good for 5 years but all taxes are paid at once. Cars from MY1976-1985 that have grandfathered collector plates need to pass emissions tests every 5 years so long as they are kept registered; that may retrofitting to cats or other emissions equipment. The plates are good for 5 years but all taxes are paid at once. Cars MY1981 and older must pass emissions testing every year; that may require retrofitting to cats or other emissions equipment. Most older cars back to MY 1982 require emissions testing every two years and definitely requires cats and other emissions equipment. Cars 7 years and newer do not require emissions testing. Requirements for where testing can be done varies by county, but AirCare Colorado testing stations are perfectly capable of testing cars that can't go on a dyno (such as 4WD vehicles, which are very common here).

So, my '67 and '69 911s are OK as-is. Your '77 'Vette without a cat is not.

dutchcrunch

Just moved to South Carolina or Florida and not deal with this crap. Man these states with emission on older cars go to friggin far. How many 1986 cars do you see in real life daily.