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like the title say i would like to here some opinions on the 258.

thanx,
Jim
 

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I had a '79 CJ-5 with a 258 and T-18 4 speed, ran great right up to the day the ring stuck, and then it just smoked too bad to drive it :oops:
So I rebuilt it............had an offenhauser 4 barrel intake with a motorcraft 2 barrel adapted sideways, torque cam, dual exit headers, shaved head for more compression......I wish I still had that motor, it would keep up with stock V-8's, and out ran a worn out 302, I would have to wonder if it would have power enough to pack a full size waggy around very well, but it worked great in the light wieght CJ :thumb:
 

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I remember that motor Steve that was awesome and now holly has that truck avenger carb in a 470cfm rating. You know you could also stroke that motor and suprise a whole lotta of poeple. I saw one of those strokers in the mud. It went everywhere. :rotfl: :rotfl:
 

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rokbrkr said:
I had a '79 CJ-5 with a 258 and T-18 4 speed, ran great right up to the day the ring stuck, and then it just smoked too bad to drive it :oops:
So I rebuilt it............had an offenhauser 4 barrel intake with a motorcraft 2 barrel adapted sideways, torque cam, dual exit headers, shaved head for more compression......I wish I still had that motor, it would keep up with stock V-8's, and out ran a worn out 302, I would have to wonder if it would have power enough to pack a full size waggy around very well, but it worked great in the light wieght CJ :thumb:
My YJ is the last year that they made the 258. I put a 96XJ head and exhaust on it with the mopar EFI kit. 30 over with a HOT cam(clifford 272). It will spank most. Lots of $$$ tho.
 

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Nothing against heavy hitter but I know some poeple who just beacuse they have big blocks they think they are the fastest thing around. One freind bronco with 38s 3.50 gears and a 460 slower than cold tar running uphill on a January day. But man talk to him and he has called his accl "scary fast"
:rotfl: :rotfl: Power to weight is where its at
 

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shootin Nate a little crap :thumb: His rig is definatly capable - especially for a daily driven monster jeep and he's a way cool guy, so he's good for it. Hard to say I'm not a little excited about my engine since I just got it back from the machine shop. It's no race motor though but it was a big seat of the pants improvement over the 6.2 diesel - and thats when it was tired. And weight is the biggest down fall of my rig - part of the reason I came up with "heavy hitter"


Ok, back to the 258 inline six :thumb:
 

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I got much love for big oomph.
some day I'll build big, but it will be my tow rig that can still wheel (a little)

I had a really in depth break down of all the projects that I have done on my motor and the jeep in my website, but it seems that it has been taken down from the net. I still have lots of information, so if you have any questions, get in touch with me.
 

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On the same subject. I have a 90 yj carb'd 4.2 and an 87 efi 4.0. If you had to choose between them for the yj which would you put in? This came up a bit in another post but I am just wondering.
 

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AH said:
On the same subject. I have a 90 yj carb'd 4.2 and an 87 efi 4.0. If you had to choose between them for the yj which would you put in? This came up a bit in another post but I am just wondering.
It is a step up, but the old renix system is pretty crappy. I would not deal with the headache of the swap to that system. Just too much work for a poor upgrade. The most helpful thing that I did (prior to MPFI) was make an HEI distributor that I wired in there. It ran really good and I disabled the stepper motor on the carb. It ran pretty good. I'll see if I can find my diagrams for the wiring. I still have the HEI that I built too. Could easily separate from it for a nominal price. :thumb:
 

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How about the carbed 4.2 and convert it to propane. It runs at angles well too :thumb:




At least that's what I hear. Mine still isn't done.
 

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yup. I picked up a 10 gal forklift tank the other day. Now I just need a bracket to mount it, high pressure line and a lockoff/filter. Hope to get the parts friday.
 
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