As a simple guideline, the Smog Equipment must be either for the motor OR
for the vehicle, WHICHEVER IS NEWER. If you put in a '90 motor, then you
have to maintain the same level of smog equipment that the motor requires.
If you install a pre-'90 motor, you must increase the smog equipment to '90
levels. If you put in a post-'90 motor, the smog equipment of the motor must
be fitted in the vehicle.

There is a guy near Fresno (center-state, California) that installs a Ford
5.0L into Jeeps. I have heard a mixed bag of comments, but he should be
worth a look ...




"Rick Sink" > wrote in message
...
> My son's 90 YJ has the 4.2L six with 5 speed. Is there such a thing as
> swapping the 6 out for a V8?...and still meeting emissions laws? Could
> the trans/clutch stay...or would the V8 require a new trans? Any way
> to get a Chevy small block in it, with emissions equipment?
>
> Rick