Hi HSVREDSLED,
As I understand it. You can use an engine that is compliant from 3 years prior to when the new standards come in.
So, right now, in Holden engines, you can use a post 2004 LS1 (Euro 3 spec), an LS2 (Euro 4) or the current L76 (Euro 4) You have up until Decmber 2008 to use the LS1, then you can not use it anymore.
The rules changed on January 1 2006. That means that the post 2004 LS1, was still compliant up until Decmber 31 2005, hence the 2008 date that you can use them. Any Euro 4 spec compliant engine can be registered now, hence the LS2 or L76 as they are current engines..
I think I have this right. I do know that the engine I have, which is a 2000 model, will not pass. So it might be the spare, that has some *stuff* done to it, and maybe make it into the Cobra one day.
Cheers