GMCpanel, I think the "vehicle or engine, whichever is newer" applies only to vehicles which originally had emissions regulations.
I don't think there are laws anywhere in the US that would require smog compliance with a 1946 model, regardless of power plant.
The crate motor is specifically marketed as a replacement for older vehicles, and not as an "2006" model. The fact that it is sold in 2006 does not imply it was certified to 2006 emissions standards.
