258 or 360?

[Petescj]

I am so torn between the AMC 258 i6 / 4.2l and 360 I dont really know what to do. The Limited obviously came with a AMC 258 i6 / 4.2l but it would need rebuilt anyway. The last few Cjs Ive had convinced me that the AMC 258 i6 / 4.2l is a great little engine. Im really happy with the 16/17 mpgs Ive been getting out of the Laredo as well. Im just not sure its what I want to put in "My Jeep".

Since Im already going to be running a SM465 behind either motor Im not worried about any breakage. I'll be upgrading my stock axles as well. If youve read this far you noticed there are only 2 choices. I dont want a Chevy 350 , Ford blah blah blah. These are the only 2 engine choices for my Cj.

I just dont know if the 4.0 head mod will be enough to make me not crave the V-8. I loved the 360 in my CJ5 , just not coupled to the T-150 and Dana 20 . The 12/13 mpgs wasnt very attractive but Im not into these Cjs for gas mileage. Either one can be set up for fuel injection so thats a wash.

Commence argument

 

[deadfeat]

I did a full 4.0l swap from a 93 XJ. Great option.. I would never go carb again. Consider a vortec v6. 4 3l. That's a great swap.

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[Old Dog]

It all depends on what you want. A V8 can make a great hot rod, hill climber or mud bogger. The I6 as you know will get more mpg's and is all you need for rock crawling.
You have 2 jeeps so why not have a 6 and a 8 best of both worlds.

 

[Hedgehog]

Oh please, oh please. Now that you've laid down the two and only two options your interested in can I follow internet norm and push every engine under the sun OTHER than the two you are really interested in? I think it really does depend on what your interested in getting out of your Jeep. Do you want raw American type horse power to get you where gearing and mediocre skill can't. Or are you interested in European type fennec where technique and gearing will get you to where you want to be.

In all seriousness, consider a V6. Great torque, with decent mileage. I put a Buick 231 V6 in my '80 CJ5 and never needed anything else. Along with that, the V6 does have history in a CJ5 .

 

[Deerejeep]

No replacement for displacement.

 

[cj7inthetwigs]

Agree with previous three. If you where like myself and only had one jeep to consider well I would stick with the AMC 258 i6 / 4.2l . I grew up in K5's and my father always said what deerejeep posted however he always had a smallblock whether it be a 383 or 406 . Its fun smoking 38's and running off from a young punk with his "5.0" but this is a 4x4 . IMO the AMC 258 i6 / 4.2l makes total since.

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[ThisGuyUKnow]

AMC 258 i6 / 4.2l with 4.0 head and 4.0 mpfi worked really well for me and got decent gas mileage with my ax15.

its a tossup both are cool engines. I'd say whichever way you decide to go you such carb and go fi. the AMC 258 i6 / 4.2l would be easier to do fi with no tuning but the 360 can be converted to fi if you are willing to do some tuning and are comfortable with putting some Chevy parts on your 360. So I guess it just depends on your end goal.

That being said when I got back into cjs I probably would have gone with a AMC 258 i6 / 4.2l again had I not been working on that 360 tune port injection kit for the last few years.

 

[PaRenegade]

It's hard to beat the low lugging ability of the AMC 258 i6 / 4.2l , as well as it's reliability. I'm curious why the AMC 304 isn't an option for you? Is it just an availability issue?

 

[harleydragon]

my favorite stock jeep,ever,was a 79 CJ7 with a AMC 304 ,3 speed so I would probably go with the 360 if those were the only 2 options..The AMC 258 i6 / 4.2l 's I had were good jeeps as well as the ones with the v6 buicks that kaiser used..But,my all time favorites have been the ones with 350's in them

 

[hole]

Fuel injected I6 all day long

 

[Petescj]

I did a full 4.0l swap from a 93 XJ. Great option.. I would never go carb again. Consider a vortec v6. 4 3l. That's a great swap.

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I can fuel inject either engine I posted. I am only interested in those 2 choices.

Oh please, oh please. Now that you've laid down the two and only two options your interested in can I follow internet norm and push every engine under the sun OTHER than the two you are really interested in? I think it really does depend on what your interested in getting out of your Jeep. Do you want raw American type horse power to get you where gearing and mediocre skill can't. Or are you interested in European type fennec where technique and gearing will get you to where you want to be.

In all seriousness, consider a V6. Great torque, with decent mileage. I put a Buick 231 V6 in my '80 CJ5 and never needed anything else. Along with that, the V6 does have history in a CJ5 .

I like the Buick. I dont like alot of the inability to get parts or upgrade it. Thats why I didnt list it.

 

[Petescj]

It all depends on what you want. A V8 can make a great hot rod, hill climber or mud bogger. The I6 as you know will get more mpg's and is all you need for rock crawling.
You have 2 jeeps so why not have a 6 and a 8 best of both worlds.

I like the 360 for the ability to give me a bit more power for climbing hills on and off road. Doubt I'll ever mud bog it at all.

No replacement for displacement.

Stolen right from my poll.

Agree with previous three. If you where like myself and only had one jeep to consider well I would stick with the AMC 258 i6 / 4.2l . I grew up in K5's and my father always said what deerejeep posted however he always had a smallblock whether it be a 383 or 406 . Its fun smoking 38's and running off from a young punk with his "5.0" but this is a 4x4 . IMO the AMC 258 i6 / 4.2l makes total since.

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35s are the top tire size for mine. Im not really looking to Hot Rod it. And when tires cost over a grand Im not wasting them doing burn outs on the pavement.

AMC 258 i6 / 4.2l with 4.0 head and 4.0 mpfi worked really well for me and got decent gas mileage with my ax15.

its a tossup both are cool engines. I'd say whichever way you decide to go you such carb and go fi. the AMC 258 i6 / 4.2l would be easier to do fi with no tuning but the 360 can be converted to fi if you are willing to do some tuning and are comfortable with putting some Chevy parts on your 360. So I guess it just depends on your end goal.

That being said when I got back into cjs I probably would have gone with a AMC 258 i6 / 4.2l again had I not been working on that 360 tune port injection kit for the last few years.

I cant see building a carb'd engine for the Limited . I think it would be counter productive. The difference in the ease of the fuel injecting could sway me toward the AMC 258 i6 / 4.2l .

 

[Petescj]

It's hard to beat the low lugging ability of the AMC 258 i6 / 4.2l , as well as it's reliability. I'm curious why the AMC 304 isn't an option for you? Is it just an availability issue?

The only AMC 304 I ever had was a whipped dog. It was abused before I got it but if Im going 8cyl Id skip the AMC 304 without a blink. The 360 is more readily available as well.

my favorite stock jeep,ever,was a 79 CJ7 with a AMC 304 ,3 speed so I would probably go with the 360 if those were the only 2 options..The AMC 258 i6 / 4.2l 's I had were good jeeps as well as the ones with the v6 buicks that kaiser used..But,my all time favorites have been the ones with 350's in them

I had a 78 CJ5 wih a 360 and 3 spd. I loved it , but it didnt crawl or work well for the style of off roading I like.

Fuel injected I6 all day long

Im really starting to lean this way. I think it may fit my style all around better. I still dream about the way that CJ5 could just pick up and go though.

 

[Hedgehog]

I muct be getting old, there used to be lots of parts available for the Dauntless Buick 225 V6 , not necesarily the 225, but the 231 and I guess there's also a 250. Ahhh for the olden days.

 

[cj7inthetwigs]

I would.go 360 or.bust! Don't worry, I will come take the AMC 258 i6 / 4.2l off your hands and if you can go ahead a make in F.I. I may even give you a few dollars for your troubles.

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[ThisGuyUKnow]

Edelbrock makes a plug and play mpfi for the 360

 

[gert]

no replacement for displacement

 

[SlowPocono]

No replacement for displacement.

no replacement for displacement

I don't feel qualified to vote in the poll but I will contribute one wiseguy remark.

"The only thing that beats cubic inches is cubic money"

 

[tjmons]

Like the low torque , low weight , and the low fuel useage of the AMC 258 i6 / 4.2l . Nothing beats a six on idling thru the trails.

 

[deadfeat]

Like the low torque , low weight , and the low fuel useage of the AMC 258 i6 / 4.2l . Nothing beats a six on idling thru the trails.

I think you meant "low END torque"

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