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Discussion Starter · #1 ·
One of the guys out on the trail this past weekend had a jeep that would conquer dam near any hill. Come to find out, he had a 6 cyl (258). He made all the "stock" V8's look like sissies. It even sounded bad a--. Anybody have suggestions on achieving that kind of power out of the old six banger. I believe the guy had a 4bbl, one heck of a cam, and headers and who knows what else in that puppy. I just need a reason to start replacing axles I guess.

JC
84 CJ7 258 AUTO M300 AMC20&M30 SOA 33/12.5'S
 

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Magic HP dust, would be my suggestion.
There is no way that a 258 without major, major, high performance work is gonna compete with a healthy V8. You will be lucky to get 200 HP out of that mill, without thousands of dollars worth of upgrades and rebuilding. Almost any V8 will start at 200 HP and be easily built to 300 or more. There must have been some sickly V8's on your run, to have them all look like Sissy's, I guarentee you, he wouldnt make my 5.0 look like a sissy.
Dont take me wrong, I know that the 258, can be built into a strong engine, Ive seen Jaffers engine, in action, and it is very healthy. I also dont believe that Big V8 HP, is the end all to beat all on the trail, but the statement that a 258 made all V8 engines look like sissies, is just stupid.
The 4.0 head swap trick, on a healthy 258, along with roller rockers, performance cam, headers, high volume fuel pump, etc. would be one route, If the magic Horse Power dust doesnt work for ya.

Jeff
89 YJ
Wow, you can get a nice tan on your arms, from welding with no shirt on.
 
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Discussion Starter · #3 ·
What you probably saw was a realy well set up drive train and suspension out do a bunch of muscle with no feet. jim

(JEEP LAW) 4 modifications per application
 
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Discussion Starter · #4 ·
Notice, I did say "stock". The drivetrain did help out. There was a couple of 304's and a 350 to be precise. He couldn't compete with the other 350 though. I agree that a V8 is far superior, but this 6 was a good one. I would love to swap a 350. I have one in my 57 chevy 2dr hd top. It didn't cost too much to put together over 350hp, but after axles, R&P, and Fenders, etc. it has been $$$$$$$.

JC
84 CJ7 258 AUTO M300 AMC20&M30 SOA 33/12.5'S
 

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ya.. my last 258 would out gun my buddies.. stock crate 305 in his jeep... that thing was nutless compared to my 258... but compared to my tired 401.. doesnt come close.. .
h8 is right.. i really good 258.. is a damn fine motor.. but.. compared to a mildly built v8.. it doesnt hold a candle to it..

listen to ole h8.. talkin trash only days after his engine swap.. what happened to that... i have a 4 cyl.. and its all i need for the rocks out here.. blah blah crap?
/wwwthreads_images/icons/wink.gif
hehehehe... someone has seen the light..

http://www.jeepgod.net

84 CJ-7 401/T-18/D20/D44/D60w/4.10&Detriots/YJ frame & tub/35x16x15 Boggers
survival is instinct, but living takes guts
 
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Discussion Starter · #6 ·
First off I like line six's. But they will not stand up to even a stock V8 in terms of HP With out Major building up. They will produce About the same Torque stock. Most likly the reason that you where so Impressed with the 6 was that you where looking at the wrong thing. Tires, lockers, gears and last but not least DRIVER SKILL; play more of a part then HP. Six's are Great engines but they are not V8's.

For what it is worth I feel I have never been held back by my line 6.

bandhmo

 
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Discussion Starter · #7 ·
I think if you build a real strong 6 then look at what you put in $ wise and the HP you got, then look at what the same $ would produce in a chevy 350 you would not be happy.I have herd several people compliment a 6 for having alot of tourque, dont realy understand why but have herd it.

(JEEP LAW) 4 modifications per application
 

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Hahaha, Jeepgod, I do sound like an HP monger now, dont I?
In all honesty, though, for the kind of trails I like to wheel, the 4 cylinder was all I needed.
The V8 swap, was the most work and money, I have ever put into the YJ, with the least amount of return. Sure it impressive, and everyone wants to peak under the hood. I get a lot of ooooohs and ahhhhs, but it doesnt go anywhere I couldnt go before, and on occasion, can even cause problems due to the almost uncontrolable wheel spin, if the throttle is even slightly over applied. It sure does drive nice on the street though(big deal). And it gets great gas mileage on the trail(better than most 4.0 mills).
I plan to use it this summer on some dunes, but my excessive hieght will be less than optimum there.
Its deffinitely not the bang for the buck, of an SOA conversion, 4:1 T case, or front and rear lockers.

Jeff
89 YJ
Wow, you can get a nice tan on your arms, from welding with no shirt on.
 
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Discussion Starter · #9 ·
Unless you want to run dunes or mudbog, a 258I6 will be all you need. I put
the MPI kit on mine so it wouldn't stall, and I put the Borla header on because
of the cracking cast iron exhaust manifold. H8 was with me last Aug. on the Dusy
when he still had his 4-popper and it didn't need any help on the rocks.

Gary
 

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Yup, Dusy, and Coyote.
And that was with the rig fully burdened with 7 days worth of fuel and supplies. That was a good lil engine. I ran it for almost a year, with no problems.
That was sure a great trip too.

Jeff
89 YJ
Wow, you can get a nice tan on your arms, from welding with no shirt on.
 
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Discussion Starter · #11 ·
He probably has the same set-up I do, I've got Clifford intake with a Holley 4bbl 4160 {600cfm}, flat top pistons, big cam { can't remeber specs }, 3 into 1 headers, Mallory ignition & distributor, it sounds just like an 8. the guy who built the engine said he would guess that it has about 275 hp. All I know is that it's got a ton of tourque and goes like hell!!!!

 

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All you guys keep on spouting "HP" like it's the Holy Grail. For a rockcrawler, it's the TORQUE were after. Alot of V8 make huge amounts of torque, but you have to look at WHERE on their RPM band it comes in. If you have to rev the motor to 3k to make torque, what good is that if you wanna go 2-5 MPH??
Now I don't have the numbers, but I know the straight 6 puts out gobs of torque right off down low where it's most useful.
Don't get me wrong, for alot of folks and their rigs v8's are ideal, but for most of us, I6 power is more than adequate, especially if your flavor of 4 wheelin is slow rockcrawling.
Bob in Ma

 
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Discussion Starter · #13 ·
So bob I have heard this before, What makes a 6 more torque'y than an 8. I went with an 8 because I like overkill with anything I bolt to the jeep. its a to big, to strong, to much, overkill, jeep thing you see. jim

(JEEP LAW) 4 modifications per application
 
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Discussion Starter · #14 ·
Has anyone driven th new gm 4200 vortec i6? I was in a chevy dealer today and picked up the new blazer brochure. The torque curve hits 260 ft.lbs at 1600, peaks at 275 around 3000 rpm, and holds right up there til the hp peaks out at 5000 something rpm. Granted, this is the chevy advertising, but if that engine really does perform that well, that blazer must be fun to drive.

I wouldn't want to be in the woods and have the solenoid actuated exhaust valves or the computer controlled throttle plate fail! What happened to simplicity? :) Brendan

Proud owner of the world's best running Carter BBD
 

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Actually for a well equipt rock crawler, torque is not as much of an issue as it used to be.
When rock crawlers were running 35" and larger tires and had T cases in the 2.4 to 2.7 range, then you needed a fair amount of torque to keep chugging along on super steep and slow obstacles. But with 4.3 and 4:1 cases and even doublers on top of that, you dont need monsterouse torque or HP. Just a smooth powerband.
I typically dont have to do more than lightly apply the throttle for any obstacle when Im in 1st gear low (132:1), hell you could just about pedal up it. I usually start off and run in 3rd or 4th gear, when on anything but vertical climbs.
Most important is smooth power acceleration at between 700 rpms and about 1700 rpms, (which I dont really have with my current cam ) My 5.0 wants to rev hard, and is kinda unpredictable at about 1400 rpms to 1900 rpms, then it settles into a smooth power band (but at that point Im revving way to high).
So I try to run at no more than 1300 rpms, which the 5.0 is very comfortable at, and has plenty of torque. It also makes for very good fuel mileage, on the trail.
Now on the street, thats a different story, the HP and torque both work well to accelerate and cruise like any other high performance V8 sports car(ie: Mustang Cobra, Z28 Camaro).
I fully agree, that for most applications the inline 6 is very capable, and more than adequate.
That new Inline 6 vortec from GM, looks like it will be one hell of an off road mill. But it has some strange features also. Like a hole in the oil pan for the axle to pass through. But still, 275 HP and 270 ft lbs torque,is a very powerfull mill.

Jeff
89 YJ
Wow, you can get a nice tan on your arms, from welding with no shirt on.
 
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