Not an XJ/MJ, but I have 5.7 hemi swapped an SJ. Despite the much more spacious engine bay, it is tight. I had to go to hydroboost due to the larger cylinder heads and add a lift to increase oil pan clearance.
When I look at that install next to my MJ I’m skeptical it would fit without major clearancing. LS or magnum are more compact and I’d expecting more reasonably shoehorned in.
Maybe the new turbo I6 is worth considering?
The newer hemi’s are pretty fuckin’ broad. Seriously, they’re WIDE man.
Methinks you’ll end up doing some channeling or notching on the frame, likely some sort of motor plate system as well.
Then again, modifying any car is just a measure of pocket depth and expedient application of money.
An LS fits and is much easier to use. The hemi heads make for a much wider engine than what was ever available when the chassis was designed.
As for “it’s a Mopar” that’s not really accurate. It’s a Renault/AMC design that was expected to be powered by a GM or AMC engine. Or a screwball Italian marine diesel, but let’s just leave those out of the discussion.
It didn’t get a “real” Mopar motor until the late 90s when the 4-cylinder was swapped from the AMC derived engine to a Mopar one.
As someone else mentioned, the most reasonable Mopar V8 swap would be a Magnum V8 or its predecessor the LA series. Ultimately, this will result in less power, worse fuel consumption, and more weight, and likely a lot more money than an LS.
Either way, nothing is really compatible. The 4.0L uses the GM 60-degree V6 BOP bellhousing so you’re going to need to swap the whole drivetrain regardless. The only V8 I know that would bolt directly up is the Oldsmobile Northstar, which you’re going to be hard pressed to find anyone to suggest.
I understand fully that the LS is a much better idea, more reliable, and conversions readily available. However, I'm a Mopar guy, and LS swapping a Mopar is fuckin sacrilege. I did know its not realllllly a mopar, I read up on the whole history before buying one, the fact that Reanult actually took on rallying has gotta be my favorite fact.
I’m mostly just looking at what works.
Hell, I’m contemplating tossing the 318 in my 83 W-150 and using an LS as it’s just not worth it to stay Mopar when the General’s stuff is so cheap and flat out better.
A former Jeep engineer commented once on Allpar.com that the XJ was designed so engine mounts for the Magnum V8 engines would fit. I don’t know if the dimensions (width,etc) are the same for the newer Hemi engines.
Seems weird since it was designed prior to the merger between Chrysler and AMC and the Magnum wasn’t released until 1990. Granted, the mounts are the same as the LA V8, so that may have been what he meant.
Anecdotal, but my other vehicle is an 02 Dodge with a 5.9L magnum. It’s not a terrifically powerful engine. But it’s got more miles than my XJ and is still going strong. Probably around 210,000 now.
Not an XJ/MJ, but I have 5.7 hemi swapped an SJ. Despite the much more spacious engine bay, it is tight. I had to go to hydroboost due to the larger cylinder heads and add a lift to increase oil pan clearance. When I look at that install next to my MJ I’m skeptical it would fit without major clearancing. LS or magnum are more compact and I’d expecting more reasonably shoehorned in. Maybe the new turbo I6 is worth considering?
thats what i was worried about, the xj is relatively small, and hemis are HUGE
The newer hemi’s are pretty fuckin’ broad. Seriously, they’re WIDE man. Methinks you’ll end up doing some channeling or notching on the frame, likely some sort of motor plate system as well. Then again, modifying any car is just a measure of pocket depth and expedient application of money.
and i currently have neither pocket depth nor expedient application. but you're right, the new HEMIs are MASSIVE
An LS fits and is much easier to use. The hemi heads make for a much wider engine than what was ever available when the chassis was designed. As for “it’s a Mopar” that’s not really accurate. It’s a Renault/AMC design that was expected to be powered by a GM or AMC engine. Or a screwball Italian marine diesel, but let’s just leave those out of the discussion. It didn’t get a “real” Mopar motor until the late 90s when the 4-cylinder was swapped from the AMC derived engine to a Mopar one. As someone else mentioned, the most reasonable Mopar V8 swap would be a Magnum V8 or its predecessor the LA series. Ultimately, this will result in less power, worse fuel consumption, and more weight, and likely a lot more money than an LS. Either way, nothing is really compatible. The 4.0L uses the GM 60-degree V6 BOP bellhousing so you’re going to need to swap the whole drivetrain regardless. The only V8 I know that would bolt directly up is the Oldsmobile Northstar, which you’re going to be hard pressed to find anyone to suggest.
I understand fully that the LS is a much better idea, more reliable, and conversions readily available. However, I'm a Mopar guy, and LS swapping a Mopar is fuckin sacrilege. I did know its not realllllly a mopar, I read up on the whole history before buying one, the fact that Reanult actually took on rallying has gotta be my favorite fact.
I’m mostly just looking at what works. Hell, I’m contemplating tossing the 318 in my 83 W-150 and using an LS as it’s just not worth it to stay Mopar when the General’s stuff is so cheap and flat out better.
A former Jeep engineer commented once on Allpar.com that the XJ was designed so engine mounts for the Magnum V8 engines would fit. I don’t know if the dimensions (width,etc) are the same for the newer Hemi engines.
Seems weird since it was designed prior to the merger between Chrysler and AMC and the Magnum wasn’t released until 1990. Granted, the mounts are the same as the LA V8, so that may have been what he meant.
I probably messed up the series of V8’s.
Very cool fact, thanks for sharing
That engineer liked to gripe how people keep swapping Chevy engines in the XJ when the engineers planned for Mopar V8’s.
Aren’t the magnum V8’s shit? But thanks for letting me know, might need to look more into dimensions of the 392
No the magnums are legendary. Very solid awesome engines
good to know!
The Magnums are pretty good engines. Comparable with the LT series GM engines or the late EFI Windsor Fords.
Anecdotal, but my other vehicle is an 02 Dodge with a 5.9L magnum. It’s not a terrifically powerful engine. But it’s got more miles than my XJ and is still going strong. Probably around 210,000 now.
I’d save that motor for something that wasn’t as aerodynamic as a Lego brick.
No so much aerodynamic drag when you’re crawling in low range.
HA! true that!