Smog pass with replacement head and EFI

[stanton]

I have a 83 CJ with AMC 258 i6 / 4.2l getting tired of the idle so I found a 91 cherokee that has body damage I thought I would buy it put the head and EFI in mine.
My question is do I need to take it some place to certified for smog?

The doner jeep and mine are California vehicle's

 

[Tommy]

Smog wise, my smog guy says if you swap the whole engine out, computer and all, for a newer one there would be no problem. Just tell them what year you swapped for, as long as it is newer, and they will smog it to those specifications the next time the smog check is due. He says it's a little trickier when you start swapping out parts. Probably best to ask the mechanic at your smog station.

Tommy

 

[Sasquach]

Air Resources Board - Homepage

It is not as simple as pulling parts from one and installing on the next regardless of them being ca. legal vehicles.
The head and EFI from the cherokee were certified on the 4.0 powerplant and approved for that vehicle.
To add an aftermarket system it needs to have an Executive Order from the above board and the only two I am aware of are the Howell TB kit and the Mopar MPI kit.
As Tommy said the entire engine package may be possible to swap but I have read several horror stories to go with that. Read up on the link above and even contact them diectly for answers.

 

[stanton]

If I go with the howel EFI for the AMC 258 i6 / 4.2l and swap out to the 4.0 head from the doner jeep will the AMC 258 i6 / 4.2l intake still work.

 

[Sasquach]

If I go with the howel EFI for the AMC 258 i6 / 4.2l and swap out to the 4.0 head from the doner jeep will the AMC 258 i6 / 4.2l intake still work.

http://arb.ca.gov/msprog/aftermkt/devices/eo/D-452.pdf
Here is the E.O. for the Howell kit just to give an idea what is changed and what is not. I was looking to see if the EGR system remains and if so you would have a hard time going to the 4.0 head because of the mating intake/exhaust manifolds and EGR, it is not mentioned but that would be of concern.
I can not say weather or not the AMC 258 i6 / 4.2l intake would work but I do know the AMC 258 i6 / 4.2l exhaust manifold will not work on the 4.0 head.