Increased displacement and emissions laws?

[SDLS1Rider]

I have a question. I once read that if you replace an engine with a higher displacement engine it would automatically fail the smog standards. If this is true would it also apply to a stroked engine? For instance if you were to take your LS1 out of your C5 (5.7) coupe and replace it with a LS2 (6.0) or a LS7 (7.0), would you be able to receive a smog cert? Another example would be if you replaced your LS1 with a 402. So the question is, if you change/increase the displacement from factory specs would you be able to get a smog cert. or would you be violating emission laws. Thanks in advance

[Wicked C5]

Originally Posted by SDLS1Rider

I have a question.

I once read that if you replace an engine with a higher displacement engine it would automatically fail the smog standards. If this is true would it also apply to a stroked engine?

For instance if you were to take your LS1 out of your C5 (5.7) coupe and replace it with a LS2 (6.0) or a LS7 (7.0), would you be able to receive a smog cert? Another example would be if you replaced your LS1 with a 402.

So the question is, if you change/increase the displacement from factory specs would you be able to get a smog cert. or would you be violating emission laws.

Thanks in advance

You can pass the sniffer the smog setup is different so you would fail if the smog guy really knew what he was looking at. Kinda like long tubes are illegal but smog guys have passed them before because they didn't catch it.

If you want to 100% legal you have to have the car refereed and they will give you a special tag to ok the motor. There thing is as long as the motor is out of a newer car then your own and has all the emission stuff they will give you the special tag. This is how many of the 3rd Gen Rx7 guys and 240sx guys have legal LS1 cars.