Help me fella's. 258 to a 360

[Hafness]

Ok. I have a 360 that I am thinking of buying. 350 dollors for a used one that the guys says only has 55k on it. Is this a good deal?? I have talked to pig smith and he has given me a lot of good advice on switching my 258 to this 360. This 360 is from a 78 and I have a 84 j10. Any and all advice is appricated.

[The PIG Smith]

Allow me to share with the group, what I my thoughts were on this topic.
Maybe others with chime and add to my list or correct me where I am incorrect:

LOTS of issues to solve.
1. Fuel line for a 258 comes into the engine bay on the passenger side and is needed on the drivers side for a 360

2. The I6 Radiator is smaller. Not a big deal you think...just get a V8 Radiator and bolt it up.
Wrong.
The Radiator core has a smaller opening for the smaller radiator.
You could replace the I6 core support with a V8 unit (easy to get, but a LOT of work)
or with a cut off wheel, just cut and grind and make the opening larger

3. You will need a 360 standard flywheel.
Might as well do a new clutch/pressure plate while it is torn down.

4. Exhaust

5. Wiring harness will different.
Some folks have hacked, cut and spliced to make the swap work.
I would get a V8 harness from the block on the firewall on out.

6. The T-176 four speed will have a much shorter in put shaft for the 258.
The 360 will need a longer input shaft and a 6" spacer that goes between the transmission and the bell.
The I6 sit deeper in the engine bay than the 360 does and needs the spacer.
The T-176 is a medium duty trans...and some say is okay behind a V8 and others say it not a good V8 tranny.
One option would be to find a T18 four speed.
The T18 is a heavy duty truck tranny that Jeep installed in J20.
There are many options for a 4 speed.
The Ford NP435
http://www.novak-adapt.com/knowledge/np435.htm
The GM NP464
http://www.novak-adapt.com/knowledge/sm465.htm

Search the forum for swaps with NV3550/NV3500 5 speed.

[mattmopar440]

sounds kinda high price for a 360 unless it was rebuilt in the last 5 years

[tgreese]

Just a comment ... "just because you have the engine does not make it a good swap."

Unless you really want the 360, a 4.0L HO from an XJ would provide a big boost in power and avoid all the compatibility problems that go along with changing from a six to a V8. The only thing you gain with the AMC V8 conversion is that the existing bell bolts up to the V8, but as pointed out, the drivetrain length is different between the 360 and 258 drivetrain. The 4.0L should give better fuel economy than the 258 too.

You may as well swap to a SBC as swap to a 360 from a 258. Adapting a Chevy to the T-176 is not that hard. Certainly a Gen II or Gen III SBC will provide better fuel economy than a 360. Nothing wrong with the 360, but engine technology has advanced a lot since the 360 was designed.

JMO.

[The PIG Smith]

Unless you really want the 360, a 4.0L HO from an XJ would provide a big boost in power and avoid all the compatibility problems that go along with changing from a six to a V8. The only thing you gain with the AMC V8 conversion is that the existing bell bolts up to the V8, but as pointed out, the drivetrain length is different between the 360 and 258 drivetrain. The 4.0L should give better fuel economy than the 258 too.
This was my second round of advice:

Swap in a late model 4.0L HO from an XJ/TJ/WJ
Mechanically, its a bolt it.

The swap would need for you to switch from a vacuum brake booster to a hydroboost unit as the intake manifold would interfere with the vacuum unit.

If you stick with EFI, there are several issues to solve.
1. ECM computer for the EFI.
MOPAR produces a complete EFI setup for the 258 using stock 4.0L parts...so a person could buy just the computer to go with your donor engine.
Also, there are aftermarket vendors selling stand alone ECM for the 4.0L I6
2. The crank position sensor will need to be relocated.
3. Electric fuel pump

You could get a high performance intake and carb for the 4.0/258 and bypass the electronic headaches.
But, IMHO, the headaches worth the effort and the $$$ spend on a brain is $$$ ahead of a intake/carb setup

A strong 4.0L can produce the same horsepower as an emission choked 360 V8 while using less fuel.

[The PIG Smith]

Hafness...there are several members within few hours drive of you.
Fort Wayne is about 3+ hours from Cincinnati
I am sure if you sponsored a WOT (Work-O-Thon), there would more than enough us to come over and help you with your project.

I am planning a WOT at my house sometime during the first of October to put my J10 back together.
My WOT plans are based on if I have enough parts by then to get the job done.

[Ristow]

Any and all advice is appricated


i wouldn't pull a 6 for an AMC V8. not that i'm against an amc v8,just that their I6 is a much better engineered engine,and very buildable. i potent I6 is very cool,and the 350.00 for the v8 will have that I6 well on its way.


also,a 55K motor is a 155K is a 255K. if it aint fresh,it's considered a running core to me.

[Hafness]

Good point. But after all the building would the 258 be near the power as the 360. I am all for keeping the 258. What would you start with. I do want to miss this deal ( if it is a deal) on the 360 but I will if I can get a ton more from this 258. I read about the efi for the dist. or maybe a carb. PIG and other have talked about 4.0 upgrade-but i want to keep it original as possible

[Ristow]

stock 360 is a real dog. a 4.0,or 258 w/4.0 head,and mild cam will run nicer.

but i want to keep it original as possible

you're wanting to pull the whole original motor...what difference does the cylinder head make?

[thechier86]

i want it original as possible
well if you plan to sell it as an antique later, a collector would notice that the vin says it has a six cylinder. if you plan to keep it, the only thing that i like more about the v8 over the six is the sound. i like my six cylinder mpg, and my 4.0 is STOUT! you can put your 4.2 and a junkyard 4.0 together to get a killer stroker motor. the fuel injected 4.0 is well worth the time and money to get it goin. also, from my experience, the 4 litre is way tougher(more durable) than the 360.

[lost1]

Pound for pound, I feel like the more modern I6 has a lot more power and economy than the old-school 360s we're used to seeing in these. I snorkeled my baby cherokee and put it through a lot of hell. The only reason we parted ways was a traffic collision and a settlement that was for less than I'd need to unbugger the unibody. The unibody was that vehicle's achilles' heel. I think most of the points have been made for the pros and cons of each swap, but let me add that the I6 will be slightly more maintenance intensive when things go wrong,(due to computers and EFI etc) and you'd better know your electronics or be prepared to pay for someone to help. I've owned a baby cherk and driven an old cherokee that had the 6-banger, and honestly I don't think you'll see as much difference in power as you think in that v8, unless you want to start rebuilding it to your own goals. Either way you go the engine's gonna be tough as nails; I'm not sure durability is something to compare fairly between the two... I also know that my wagoneer is worlds easier to work on than that '00 cherokee ever thought of being.

[Hafness]

Ristow, I know you talked about a potent I6. How would you make it Potent. WOuld you do a efi, Intake, Carb. What is your opinion

[The PIG Smith]

Here is one way to get a lot of zip for your 258's do-dah:

Install a modern 4.0L HO head on a 258 block.
http://www.geocities.com/035jeep/40L.html

You want stocking looking...well, from the outside, they look the same!

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Next, here are pics of what some AMC Eagle owners have down to swap their tired 258 to a 4.0L powerhouse.
Okay..these are station wagons, but the swap is no different for a car as it is for a truck:

http://www.ifsja.org/forums/vb/showthread.php?p=974007#post974007

Check out the pics I took near the bottom and then Flint's new DD he just bought.
Both these 80ish model cars are powered by late model 4.0L.

[Ristow]

Ristow, I know you talked about a potent I6. How would you make it Potent. WOuld you do a efi, Intake, Carb. What is your opinion


Cecil14 has done a lot with these I6's,and is my go to guy for any I6 info,give him a holler,he'll be a good help.