What engine in a J10

[tj10]

Well im trying to decide wether or not i want to build-up my 258 or swap in a 360. My j10 originally came with a 258 so i know it will be a bit of a pain to swap it in but my 258 has NO power. I was looking on clifford performance and they claim with these parts they can get 210hp and 360lbft of torque.

Here is the Clifford Performance COMBINATION 6=8.
This Head is available in cast iron or *new Cast Aluminum Hi Port Cylinder Head. This system will take your Jeep 258 to 210 HP and 360 Ft Lbs of Torque, peak Torque is 3,300 rpms, but you can go to 4,800 rpms with power.
1 Dual Headers
2 Ram Flow Intake Manifold Water Heated
3 500 Edelbrock 4 brl carb
4 264 Duration Camshaft, Hyd lifters & Chrome Molly Pushrods.

Does anyone believe you can get that kind of power out of a 258? Wouldnt that be on par with a 360? Any info would be greatly appreciated.

[Cecil14]

Yah you could easily get that kind of power out of a 258...but what do they want for those parts? Their head isn't really THAT much better than a standard 4.0L head, they've just done all the work for you. They not changing any of the internals of the engine, just how it breathes. Get a good 80's aluminum intake and a 4.0L head, throw a decent cam in it and you'll be more than happy with the results for a LOT less money.


aa

[janie]

I can't comment on the Clifford Performance Combo, although I'm sure the others will be along soon to chime in.

I can tell you the 258 is an excellent engine, and as much as I curse AMC once in awhile, they did have their heads on straight when they produced this six banger motor.

[Knucklehead]

I love the sixes.

I had in my j-truck a 360, 401, 401 built, and a stroked 4.0L (4.6L) six. I must say that I like the 4.6 the best. I does great on gas, has plenty of power and very smooth low end torque (like 500 rpm grunt). It will run 75 mph with 35s and 3.73 gears and has plenty of power to pass. And, this is all at 5,000'+.

I would not give clifford any moeny for what I can do myself.

Do a search, there is a ton of info out there on 4.0 heads on 258s as well as strokers.


Jon

[tj10]

Thanks for all the info guys. I already have a complete 93 4.0 head. I was just planning on buying a clifford cam and intake manifold. So you guys think it would be worth it then to rebuild the 258 and do some upgrades?

[GWChris]

Do what you can to keep the mileage up - if you're going to put significant effort and money into it, you'd like to be able to afford to drive it as long as you can. Gas prices will only continue going up.

If I could choose, I'd have a stroked AMC six, a 5 spd, and keep the FT 4WD - but I know that combination doesn't work (with a NP229 anyway), and I cannot justify the cost / effort of changing it anyway.

[LaJ10]

The six is a good motor from the start.Adding the 4.0 head makes it better.Then you can go with a cam for whatever fuel setup you are going to use.Fuel is choose ,I think more than anything,you can go motorcraft 2 barrel,weber,clifford or offenhauser intake and four barrel,or even EFI.When I did the 4.0 head I noticed my biggest gaines in higher rpm range.With the stock head I ran out of power at lower rpms than I thought I should.

[Cecil14]

Don't bother with a stroker. While a great engine the extra expense and fuss will simply never justify the extra .3-.5 liters. I'm running one in my truck now and it is a great motor (second one I've built), if I were to do it again, though, I'd find a good 258 and build that with a 4.0L head. All around the 258 is just a lot better engine than the 4.0L.

For a cam be careful. Clifford spouts out huge numbers but a lot of their stuff is built for cars...ie: high rpm. Personally I like comp cams. Whichever you go with keep it relatively small, nothing radical. You won't be happy with a huge cam, I promise. lol

aa

[chakaD460]

What carb are you running?

Have you done a tuneup recently. It sounds like your 258 might just need a little TLC.

[tj10]

It has a brand new rebuilt carter 2 barrel from advance auto parts. It has fresh wires plug cab and rotor and fuel filter. The motor does have quite a bit of lifter noise and i think excessive blow-by. The truck also has a new 2 1/4 exhaust from the exhaust manifold back with a turbo muffler and a electric fan conversion and the truck is still a slug. It has no power offroad in high I have to run it in low and still at times wish for more power even in low.

[Kali]

Those clifford numbers are closer to a stock 401.

First.... You have 32" tires with stock gearing im assuming. Might want to change to 3.73s (or even 4.10s if you use it more for trails). Stock gears (3.31 or 3.54) with 32s would make even a strong I-6 seem a bit sluggish with an auto.

Although I have no experience with the clifford package, I think its a great package. Sure its pricey, but I dont agree with Cecil when he says thier had isnt justifably better than the 4.0s. Maybe not entirely worth every penny, but I would be willing to bet a blueprinted, ported clifford head is better than a stock 4.0 head by a lot. Plus the clifford cam is all about low rpm grunt, so its not like clifford is selling you 360ft lbs of torque at 5,999 rpms right before your 258 explodes.

Of course if youre going to go with the clifford package youre probably going to end up sucking down gas similar to a stock 360 or 401.

Since I bought my truck ive been on the fence about what to do. Ive convinced myself that Ill just wait til the 258 doesnt run anymore and then make a split second decision

[dngrs1]

Don't forget if you swap out the I6 for a V8 you get a lot more weight in the front end.

[Cecil14]

Originally Posted by Kali

Although I have no experience with the clifford package, I think its a great package. Sure its pricey, but I dont agree with Cecil when he says thier had isnt justifably better than the 4.0s. Maybe not entirely worth every penny, but I would be willing to bet a blueprinted, ported clifford head is better than a stock 4.0 head by a lot. Plus the clifford cam is all about low rpm grunt, so its not like clifford is selling you 360ft lbs of torque at 5,999 rpms right before your 258 explodes.

Don't misunderstand me , I'm not saying the clifford stuff is bad. I just don't think it's worth anywhere near what they charge for most of it. But it's like most things, there are people with more money than brains or ambition. Someone will buy it and be very happy with it.

If you're looking at the aluminum head then yah, it's gonna be a TON better and there's nothing you'll ever do to a standard 4.0L head to compete. However, you can put your own big valves in a 4.0L head, put new springs on it, port it, whatever you like. I really don't think it'd cost what they want, especially if you can do most of the work yourself.


aa

[tj10]

I have the stock gearing. Whats the steepest gears I can go before I have to swap out carriers? I thought it was 3.73's.

[Knucklehead]

The only real advantage an aluminum head has over a stock cast iron 4.0 head, is that you can run a full point higher compression, where the iron head will detonate.

The flow numbers of the clifford head are not that great and the bigger valves WILL adveresly affect the low rpm perfromance. The MOST IMPORTANT flow number is that measured at .100", .200" lift. This is where the velocity is highest and what will generate more swirl and ram effect---torque. It is where the valve will be twice as much of the time as it will at full lift. Also, I don't know the numbers of the clifford head, but doubt that you will notice any difference over the 4.0 head, driving the truck.

I agree with Cecil, get a good comp cam (I use the 252 XE, but it is noisy due to the steep ramp angle on the lobes). Put an HEI of a chevy striaght six (use an AMC 360 gear), ford 300 six wires, a motocraft 2 barrel off a 304, and you will be very happy.

These sixes shine, most, at idle-off idle under 2500 rpm. And that is where you spend 99.9999% of your time. My wifes 2000 chero sport turns 2,200 rpm at 70 mph in 5th, and gets 22 mpg (FWIW).

You got a 4.0 head. Use it, save $$$. If you got the $$$$ to burn, get it...it will sure look "purdy".

That's my pennies worth....