91 Jeep Cherokee 4.0 engine transplant.

Hard to say, the cross says 84-91 on the shortblock. I'd be checking every bit and the mount positions. :/

More than likely the only changes are some new bosses cast into the block for attaching accessories.

I've never heard of anyone having any major issues bolting an HO into a non-HO or for that matter Renix based injection (french as Bill alluded to) older 4.0 being replaced with the newest 4.0's...

Differences include intakes with bosses for brackets what don't line up with older brackets (just drill new hols or use newer brackets), a coolant temp sensor bung that was relocated on the newer head castings (93 and newer I believe). The old bung is still there only capped by a bolt, which when removed allows the old coolant sensor to work. A newer (post 97) intake design (rounded runners) that flows somewhat better than the old square ones but still bolts up to older heads. and lots of minor BS mounting point relocations that don't matter a damn bit as long as you get the engine complete with those parts.

Basically nothing that can't be overcome with a drill, a welder and a small amount of modification. And not even that much if you get a complete engine.

Lots of folks have posted about swapping the different years with success.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

I'm not sure which manifold you're talking about... the exhuast manifold changed but the port pattern is the same so it's just a matter of swaping manifolds, or fab'ing or buying a new collector pipe, and modifiying brackets for clearance. The intake manifold also has the same port pattern and is 100% interchangable from Renix to non-HO mopar MPI, to HO, to even the newest intake (99 and up rounded runners). In fact you can even use an old 4.2L carbureted 2bbl intake manifold on a 7120 or 0630 head. Those are both HO "high port" heads without the 0331 head's penchant for cracking.

Again this might require some minor drilling, grinding, maybe even some welding to get workable brackets and power steering but if you're doing an engine swap and the thought of drilling, grinding and welding scares you then you probably ought re-think doing it. :)

Sorry Bill, but you are mistaken. Folks swap the 4.0 head onto the 4.2 engine all the time. 'I' don't like the idea of relying on epoxy to hold the coolant passages, but hey that's me.

You only have to change the exhaust for the 4.0 header, the intake matches up just fine so the carb can go back on the 4.0 head.

So in other words, you can junk the fuel injection on a 4.0, drop in a cam and go with a carb and maybe a nice 4.2 performance intake to 'really' get some power out of it. :-)

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail >

Ok if I e-mail you a picture of my 88 YJ's black powdercoated 2bbl aluminum intake bolted to a 0630 4.0 head and Stainless OEM style 4.0 header with a small sign that reads "Bill is wrong" will you post it and admit the sign is correct?

I'll tell you if you really want some power out of a Jeep 6, do a 4.0 stroker, the 4.6 (or more) with a 4.2 crank and rods is a real eye opener if you're used to the 4.2 or 4.0... It's not hard at all to put down more RWHP than a stock Mustang 5.0 with a mildly messaged stroker.

The 4.0 w/ FI is definitely a better bet for power than ANY combintation of upgrades with a 4.2, (short of forced induction). I know you're fond of that old turd of an engine Mike but lets face it that thing was rated at just over a hundred hp and torque in it's day... And that might have been optimistic or even flywheel numbers... The 4.0 whips the pants off it in just about every regard. I own and wheel all three engines and I'll never build on a 4.2 again... waste of time.

No Bill I've actually done the 4.0 head swap and used the 258 intake manifold so the person who is assuming is YOU... See how that works? It's pretty simple really.

Pic will be mailed in the next day or so, I'd send you a pic right now without the "Bill is wrong" sign but that wouldn't be nearly as much fun :)

You can post it over on alt.binaries.pictures.autos.4x4 for all to admire.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

Well, I have an extra 4.2 sitting in the garage with a freshly remanned crank and bearings and a tired 4.0 I am removing from my 'new' 87 Cherokee to play with. Have a 'new' engine out of my 88 Cherokee for the 87. Hmmm.....

I don't know what I have done to my 4.2, but it goes like a scalded cat as it is. It will top 4400 rpm and hit over 50 mph in 2nd, a fast 75 mph in 3rd, bury the speedo in 4th and who knows in 5th.

The best part is I still get well over 20 mpg on the highway.

I plan on playing with the two spare engines and build myself a stroker for when mine wears out.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

Bill, offroad.com shows it works just fine plus lots of folks use the

4.0 head in their 258's and keep the carb.

It's just the exhaust that doesn't fit, you have to use the 4.0 header.

Mike

"L.W.(Bill) Hughes III" wrote:

I've sent you an email prepare to eat crow.

Those pics are terrible, and the port pattern is identical ... maybe you've confused the exhuast ports which are different with the intakes which are identical.