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Hello I have a 1976 corvette and I’m wonder how I can make it pass smog as I just finished rebuilding the car? How would I make my chances of passing better and will I need to have anything done to it for it to pass? I’m in California and it is a l-48 350engine and automatic transmission.
If your engine is running well, with carb set up properly and your catalytic converter in good working order, you shouldn't have any problems passing emissions standards.
Unless you no longer have all the stock emissions stuff still on the engine.....then, depending on the CA county in which you live, there may be some issues.
Top off with some good Hi Test gas and drive car on freeway hard and fast for about 50 mile RT then go straight to SMOG shop for testing. Used to have gas tank about empty and put gallon of Denatured Alcohol in then high speed before testing....now can’t buy the stuff in CA.
Top off with some good Hi Test gas and drive car on freeway hard and fast for about 50 mile RT then go straight to SMOG shop for testing. Used to have gas tank about empty and put gallon of Denatured Alcohol in then high speed before testing....now can’t buy the stuff in CA.
Agree, run that puppy in there nice and hot. I used to lean out my carb about a quarter mile from DMV. As soon as I left I would tune it back.
Yep. If it won't pass "as is", you need to retard the ignition a few degrees (makes the combustion chambers run hot at idle and burn off excess hydrocarbons, and lean-out the carb. It needs to start and keep running on its own...but that's about it.
For those with the CEC emissions control stuff on the early 70's cars, this is exactly what the CEC system is intended to do: retard the ignition at idle and low cruise conditions so that the combustion chambers run hotter.
I recently had a neighbor who was having a heck of a time getting his CA car to pass smog. It ended up that the smog place he went to had been red flagged for being suspected of being an "I know a guy" shop and by random he was forced to go to a referee station. The good news is that the referee station is totally on your side and wants to do everything they can to help you out. There is some law that says if your car can't pass (assuming it's not a gross polluter) and the cost to get it in compliance is above a certain amount, you can go to a referee station. I would research the law and even talk to a reputable shop and find out your options.
There is a very easy way to renew registration without s smog test
Originally Posted by Joshua Ruiz
Hello I have a 1976 corvette and I’m wonder how I can make it pass smog as I just finished rebuilding the car? How would I make my chances of passing better and will I need to have anything done to it for it to pass? I’m in California and it is a l-48 350engine and automatic transmission.
If you had previously registered the car in California, all you have to do is a change the address on the registration to a county that does not do bi-anual smog tests, like Imperial County. Send in a Planned non-operation with the $8 and a change of address, and you will get a new renewal bill that does not require a Smog Test.
You will only need a test when you sell the car.
Last edited by J. Carlos Fox; Dec 4, 2020 at 01:07 AM.
Or sell it and get a pre-1973 1976 model which does not require a smog test.
Fixed it for ya. Its 1975 and older that do not require a smog test. Guy missed it by a single year.
However it is worth noting that tampering with smog equipment is technically a federal crime, even if it is rarely, if ever, enforced on vehicles this old.
Were still supposed to have the smog stuff on in case of a spot check but who does?
Unless its super loud and driving like a fool I wouldnt sweat it...if anyone did it would be CHP
From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by Joshua Ruiz
Hello I have a 1976 corvette and I’m wonder how I can make it pass smog.
Retard the timing to no more than the emissions decal timing spec (usually about 6 to 8 degrees initial). Make sure the vacuum advance is on a ported vacuum source (no vacuum advance at idle, or disconnect the vacuum advance completely). Make sure you have adjusted your carb idle mixture screws to produce a 25 - 50 rpm lean idle drop. Make sure your catalytic converter is functional ("shoot" inlet versus outlet temp with an IR gun and verify significant temp rise through the converter). This will get both HC and CO down pretty low.
Lars
From: Loud, Raw and Dangerous 1968 327 4S in Southern California
Originally Posted by Duane4238
Have you ever thought of leaving California?
Duane
Not me...I went cruising today with the top down and it was in the 70's. The only time I put the top up is when I leave it at the hot rod shop for some repairs.
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Tips for passing smog(CA)?
Good one!
