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Who is running an AMC V-8 in their XJ/MJ?

I

IdahoEagle

NAXJA Forum User
Location
Boise Idaho
I have an 86 2 door XJ with the 2.5/AX-5/207 soon to be 208 combo. It has a disconnect 30 and non-c-clip 35 with 4.11s on 31s with a 2" lift soon to be long arm. I'm eventually going to do an engine swap and have always been an AMC nut. The plan is either a 360 or 401 with TBI so I can keep it emissions legal and use an AX-15 behind it with a set of Dana 44s also with 4.10s and step up to 33s with the same lift and help of the Napier flares I just ordered... I know a few people on here have done that basic engine swap. I'm looking for pictures of your install and what issues you had making it fit/work under the hood... I don't have a high post count, but I have been a member for several years and far from an amateur. I've been a Jeep mechanic for over 20 years...
 
The 4.0 makes 15 hp more than the 360, not worth the time, effort, cost etc. If I were going v8 I'd go with something much more modern, powerful, lighter and fuel efficeint like an ls.
 
What he said.

AMC guys ditch 360's and 401's to swap 4.0's in...
 
Bloose put a 5.2 Magnum in his 00ish XJ. It's not AMC, but a Chrysler V8 nonetheless. I don't think he has a build thread, but he would probably send you pics and info if you PM him.
 
Color me confused, and not knowing Idaho emissions laws (not seeing how tbi on a old v8 makes things emissions legal) but if he want to take a stock 70-71 360 or 401 and throw something like a terminator intake on it I think it will make a few more horsepower than a 4.0 especially being the stock 360 was 295hp. Yea it doesn't make sense to take a late 70s or 80s 360, (no late 70s or early 80s v8 makes any sense in anything) but being the last year of the 401 was 79 I'm assuming you are not looking for an 80s or 90s amc v8. But you know just throw an LS at it, they are pretty much bolt in and that is what the cool kids are doing.
 
The way the emissions code is written for the county I live in, the engine has to have similar emissions equipment or better than what the existing engine has. My XJ only has TBI, EGR, and a cat. So that's all I need to pass the visual inspection. It has to run properly in order to pass the sniff. I want to run the AMC because it's cheaper for me to set up overall and they really aren't difficult or expensive to get 300+ horse out of. And besides, have you heard a nice 360 or 401 in person? They definitely sound better than a small block just about anything. And I'm expecting low to mid teens for mileage. I know swapping in a 4.0 is fairly easy, except for firewall clearance with mine being an 86, but they are way too common. I'm the guy that's solid axled a couple different AMC Eagles and put V-8s in both of them to be different...
 
One of the reasons I got my MJ.. for free, is that the guy I got it from had a 401 that he wanted to put in it and realized it was WAAAY too much work.
You would be better of with a 4.0L/stroker or GM LSx swap.
And like cal said, pretty sure 1986 2.5L was carb'd . I know some of the GM 2.8L had TBI.
 
My 86 XJ has a TBI, it was the first year for it. Jeep used it from 86-90 on the 2.5s. None of the Jeep application 2.8s had anything other than carburetion.
 
I know there is a Jeep tech on one of these forums that has a 2wd MJ with a built, injected 401 sitting in front of an AW/4 that works the way it should electronically that drag races it and still drives it on the street. He replaced the 180-ish horse 4.0 with the wonderful sounding 450-ish horse 401. Not much of a weight gain going to that V-8 over the inline 6... I have owned a couple 4.0s, a couple Magnum 5.2 ZJs, this TBI 2.5, several 360 powered full size Jeeps. The AMC V-8 has a great deal more low end and midrange torque and even though the horsepower numbers are claimed as low as 195 in the worst smog killed years, it sure moves the 4,400 pound Wagoneer with lousy gears down the road as good or better than the 190 horse 4.0 H.O. moves the 3,000-ish pound XJ. AMC V-8s benefit tremendously from a mild cam, better intake, and slight bump in compression.
 
That's the guy. I see it's been a really long time since he was on here last... Does anyone have contact with him offline? I have questions that he might be best able to answer for me...
 
Try posting in the Colorado Chapter. One of the locals may have that info.
 
you say there is no way, but for less money and complication a stroker has more power.

still, FSJ guys who have 360's swap in 4.0's to replace them for a reason.
 
The FSJ people who swap a 360 for a 4.0 just have no clue how to work on the 360 to improve it over the smog killed engine they left the factory as. I've seen a lot of people do engine swaps because some moron said that nobody makes performance parts for them anymore and nothing can be done to improve them over factory specs. The AMC V-8s are like anyone else's V-8s, it just takes a little research and know how to use tools and you can get good power with reasonable mileage out of them.
 
Why be one of the 4.0 sheep when you can start your own heard? It's yours. You can do what you want with it. If you step on toes, oh well.
 
No way on earth a 4.0 can compare to a AMC V8.

We have one in a gremlin right now that is mild on pump gas that puts 510 to the rear tire. Show me a 4.0 that will come close to that.
 
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