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post #1 of (permalink) Old 07-03-2001, 03:51 AM Thread Starter
 
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rebuild or swap?

I have a 258 in my jeep now that has I don't know how many miles. the odometer says 18k, but I wonder if it is 118k or 218k or more. Anyway my point is do i rebuild the I6 or do I swap in a Chevy 350? I already have 2 350's in my garage that will need rebuilt. My question is, will a V-8 be too much power for the stock axles? Or should I just freshen up the Six and spend all the money I would have to on adapters and put it into a cam and such?

By the way how many miles can you get out of a 258?


76 CJ7, 258,Jeep T18, D20 TC, D30 & AMC20.
4" Superlift, 33" SSR's
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post #2 of (permalink) Old 07-03-2001, 06:57 AM
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Re: rebuild or swap?

I would not put the 350 in unless you upgrade the axles. Even a tired 350 can trash the stock axles and I'm talking just on the road. If you do any off road, the axles won't last long. If you got the money to upgrade and you don't mind the gas mileage, I say go for it. I love the sound of a good V-8 in a Jeep.
Now myself, I plan on rebuilding my 6. Mine is a daily driver during the week and gas mileage is a concern for me.

Rick
80 CJ7
258 T176 TR upgrade
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post #3 of (permalink) Old 07-03-2001, 07:13 AM
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Re: rebuild or swap?

I respectfully disagree. I have run a Juiced 304 which had much more torque and horses than a freshened up 350 with 35" tires on the original 30/20 combo only change I made was 1 peice axles in the back. It was a daily driver for 4 years with weekend obuse in Tellico with not a single axle or transmission problem. Unless you are a hammer down listen to my V8 kinda guy who only knows 2 speeds on and off you shouldn't have many if any problems.

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post #4 of (permalink) Old 07-03-2001, 07:26 AM
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Re: rebuild or swap?

Go with the 350, putting hop-up parts in a 258 is a crime against nature.
There is no such thing as too much power, it's a matter of timing, if you use your head, those axles will never notice the difference. With the v-8 you will have enough motor to handle any future modifications with ease.

post #5 of (permalink) Old 07-03-2001, 09:16 AM
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Re: rebuild or swap?

i dont know where you get the idea that the 258 will help you with fuel milage. i know guys who get much better milage with thier 350 than i do with my 258 (i get 10 MPG on a good day.) 258's are notorious for being gas hogs, while 350's get pretty good milage, for a V8. unless you are gonna be mud bogging or sand dragging, the 350 is a waste of time. the 258 is a stump puller. the torque per cubic inch incredible, and it is all about torque when rock crawler. anybody will tell you that horsepower means nothing when rock crawling. why do you think diesels are used in the military, and as tow trucks? not because of thier horse power output, because that can be as low as 150 hp, but the torque output will be to the tune of 350 to 400+ ft/lbs!

just my 2 cents!

JUSTIN

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83 CJ7 258 T5/D300 4"lift locked AMC20 1pc axles 3.54
post #6 of (permalink) Old 07-03-2001, 10:02 AM
 
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Re: rebuild or swap?

Im gonna repeat what I said in an earlier Torque/HP discussion, last week.
A new generation V8 is gonna produce more Torque than you will be able to generate with any readily available in-line 6. You guys who are using the age old philosophy(which has been a good argument in the past) that the in line 6's will outpull a small block V8, are about 15 years behind current technology. V8s have come far in the last decade or so in their ability to produce great power curves.
Next point, in a well built Rock Crawler, you do not need monsterouse torque. With the gearing we are running, you could just about peddal the damn thing up most obstacles. You will more often than not, be ideling at no more than 1400 RPMs, and the demand from the power plant is no more than a well running 4 cylinder can easily generate. It is most improtant that you have a smooth usable power curve, with no eradic tendancies, in the lower RPM range, and the ability to maintane smooth power on any angle. Cool operating temperatures, and good oil pressure at low RPMs are also very important. A newer generation FI V8 easily fits the bill for these requirements. But a V8 also gives you the versatility, to run Sand and Mud at respectable, and even competetive, performance levels. Highway performance is awesome with a V8, and fuel economy will rival an in line 6 with a well tuned EFI version V8(I get about 12 mpg, on the road). Fuel economy on the trail, is excelent with a V8 and a sensible happy foot, I have been squeezing more trail miles per gallon with my 5.0 HO than the 4.0 HO's, I regularly run with, the reason being that the V8 rarely has to do more than idle all day long.
So, is a V8 a better Rock Crawling Engine than a strong inline 6?, I dont think so, and Ive ran both the 258, and 4.0 in my YJ. Is the 6 a better engine than the V8?..No!! The V8 and inline 6 are basicly a push(considering both are well tuned and performance spec'd propperly). Is the V8 more versatile? Yes!! And the V8 has no short commings, that I can think of, as compared to a 6(other than the increased potential of drivetrain breakage).
You Rock Crawlers who are still living in the early eighties, touting the advantages of the Ford 300 IL6, over the 302 CID, really need to upgrade your gear ratios, or look more closely at the performance numbers of modern day EFI V8's.

Jeff
89 YJ
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post #7 of (permalink) Old 07-03-2001, 01:43 PM Thread Starter
 
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Re: rebuild or swap?

I live in Missouri, so there isn't too much rockcrawling to do around here. I mainly play in the mud (lots of that here) and trail ride. I was checking on bellhousings and clutches for a swap to my T18 and it was going to be like $800 from 4WD hardware. $800 would almost pay to have the 258 rebuilt.
I called Clifford Performance and they have a 4.9L stroker kit for the 258. It comes with a new crank and new slugs and new rods all of it balanced, plus a new 4.0 head that has been ported and fitted with oversized valves, for the low price of only $2200!!
Which would be badass but is a little out of my budget. My wife would skin me alive if I spent that much on a rebuild kit plus all the machine shop work.. LOL
Does anyone know where to get the bellhousing and clutch and motor mounts for the V8 chevy any cheaper?
Does anyone know where I could get a 304? that would drop right in..thanks for you help guys, Wade

76 CJ7, 258,Jeep T18, D20 TC, D30 & AMC20.
4" Superlift, 33" SSR's
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