Are 258's interchangeable? - JeepForum.com
 1Likes
Reply
 
LinkBack Thread Tools
post #1 of 20 Old 10-15-2019, 08:08 PM Thread Starter
twoscooterz
Registered User
 
twoscooterz's Avatar
1986 CJ7 
 
Join Date: Oct 2010
Location: Eastsound
Posts: 109
Are 258's interchangeable?

This might be a dumb inquiry....I recently discovered that I need to replace/rebuild my 258. I have a very limited budget. A buddy has a line on a rebuilt '74 (I think) 258 for $1k - block casting #3213867. I'm told it was a surplus fleet engine that was completely rebuilt and has been on the shelf for years. I need some help confirming whether it is a 1974 and whether it will bolt directly into my '86 CJ7? Wondering what works and more so, what won't work? My CJ has no emissions stuff and I've added an aluminum valve cover, Weber 38, DUI, and SS header - which I want to reuse. Will those parts, plus a stock intake, motor mounts, T-5, clutch etc bolt up? Aside from a small drop in HP and torque, any reason to not swap my '86 for an early 258? Will it "drive" differently? Good solution or bad idea? Thanks for any help.


'86 CJ7 Laredo, 258, Weber 38, DUI, T5 w/Hurst shifter, 4.56 Dana 30, AMC 20, Detroit TruTrac, Moser axles & Blue Torch truss, Dana 300, stock YJ springs SUA, 33" MTR's, Poison Spyder sliders, NewGen tank cover, Warn 9.5ti w/synthetic rope
twoscooterz is offline  
Sponsored Links
Advertisement
 
post #2 of 20 Old 10-15-2019, 08:29 PM
RevScott
Registered User
 
Join Date: Sep 2019
Posts: 47
Cant comment on interchangeability, however, I had a 76 Cherokee S with Quadra-Trac pushed by a one barrel carter on a 258 that would idle up the side of a brick wall, and that isnt a joke, I used to have pics of it at a demolition site standing against a wall at about 45 degrees before the tires started to slip... I miss that truck,,, I didnt fuse the aux lights that I mounted on the roof rack in the right place, wires shorted insulation burned through and landed on the fuel line to that stinking one barrel. Hence Ive become very anal about wiring things to minimize risk. I put a lot of time in that truck, both working on it and using it as a mobile bed when hunting and fishing
RevScott is offline  
post #3 of 20 Old 10-15-2019, 10:03 PM
CSP
Registered User
 
Join Date: Aug 2002
Location: Colorado
Posts: 17,023
The only thing on your list that I see which wont work is the valve cover.
CSP is offline  
 
post #4 of 20 Old 10-15-2019, 10:59 PM
Trapshooter
Web Wheeler
 
Trapshooter's Avatar
1986 CJ7 
 
Join Date: Mar 2007
Location: Jacksonville
Posts: 2,353
As far as I know a 258 is a 258. Dimensions should be the same regarding the block and the mounting position. If you get a chance post some pics of the '74. Maybe someone here on the JF can see something that may help.

Good Luck..........

'86 CJ7, 258, Carter BBD, Nutter'ed, TeamRush'ed, T-18, Twin Sticked Dana 300, D30 Frt-Pwr Lok L/S-4.10, AMC 20 Rear-Mosers-Detroit Locker-4.10, 2.5 BDS Lift, 1" Body Lift, 33" Wild Country M/Ts, Black Spoke wheels

'45 CJ2A, L134 Go Devil, T-90 Tranny, Warn O/D, T-18 T-Case, Dana 25 Frt, Dana 41 Rear, 531st CJ made

My 401 build:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Trapshooter is offline  
post #5 of 20 Old 10-16-2019, 08:33 AM Thread Starter
twoscooterz
Registered User
 
twoscooterz's Avatar
1986 CJ7 
 
Join Date: Oct 2010
Location: Eastsound
Posts: 109
Good call Trapshooter. Here are a few photos to peruse. Glad to hear - so far - that it will likely work. Any potential clearance issues relating to the oil pan? I wonder if there are variations on configuration - like CSP mentioned about valve covers?

The price seems decent for a zero-mile rebuild. I'm also assuming that since it was a fleet engine that they didn't cut corners when putting it together. At least that's the hope - no way to really know.
Attached Images
     

'86 CJ7 Laredo, 258, Weber 38, DUI, T5 w/Hurst shifter, 4.56 Dana 30, AMC 20, Detroit TruTrac, Moser axles & Blue Torch truss, Dana 300, stock YJ springs SUA, 33" MTR's, Poison Spyder sliders, NewGen tank cover, Warn 9.5ti w/synthetic rope
twoscooterz is offline  
post #6 of 20 Old 10-16-2019, 08:43 AM
John Strenk
Moderator
 
John Strenk's Avatar
1976 CJ5 
 
Join Date: Feb 2005
Location: Shalersville Ohio
Posts: 19,320
See if there is some way of determining if it's a 258 and not a 232.

I had some fitment issues with the alternator/compressor mount from a 258 to a 232.
[edit] As determined below in the chart, It was a 258 and not a 232. Go figure![/EDIT]

These 3 hole looked right at first:
Name:  OBAMounting points.jpg
Views: 34
Size:  65.4 KB

But were severely miss-matched when I tried to mount the bracket up.
Name:  OBAMishole1.jpg
Views: 33
Size:  65.4 KB

Never did figure it out and I got rid of the block later as I already had a spare engine.

Yes, valve covers are different and good luck if you try to find an aluminum valve cover for it. It would have to be used as I could never find a new one listed anywhere.

Another inconsequential difference is the size of the head bolts, but that won't matter to you.

I did have a problem attaching my 84 exhaust to my 76 engine block but a little filing on the outer most holes took car of that. All the rest of the 84 intake and exhaust worked fine.

Make sure the mounting bosses for the PS pump are there. They were on both my 76 block and 84 block.
Name:  MNTBOLTS.JPG
Views: 38
Size:  170.0 KB

Also it looks as if the block is tapped for the temp gauge sending unit to fit at the front of the block instead at the top rear of the head.
block-temp-gauge.jpg
Trapshooter likes this.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


I drive a Prius to save money and buy more Jeep Parts....
John Strenk is offline  
post #7 of 20 Old 10-16-2019, 08:45 AM
cdt540
Registered User
1983 CJ7 
 
Join Date: Nov 2012
Location: Austin
Posts: 299
According to the casting table I have it is a 1970-72 258.
Attached Files
File Type: pdf Block Casting Table.pdf (85.2 KB, 13 views)

Chris
'83 CJ7 (258 5 spd)
Austin, TX
cdt540 is offline  
post #8 of 20 Old 10-16-2019, 09:01 AM
John Strenk
Moderator
 
John Strenk's Avatar
1976 CJ5 
 
Join Date: Feb 2005
Location: Shalersville Ohio
Posts: 19,320
Quote:
Originally Posted by cdt540 View Post
According to the casting table I have it is a 1970-72 258.
Awesome !!
According to that chart, the problem I had fitting the the alternator /AC bracket was a 258 also! Go figure.

Same years as yours. And that one had the block mounted Temperature sending unit also.

Well just beware if you have AC, the bracket might not work. If you just have an alternator, that bracket will fit.

Now I'm going have to change my post above....
Attached Images
 


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


I drive a Prius to save money and buy more Jeep Parts....
John Strenk is offline  
post #9 of 20 Old 10-17-2019, 07:42 AM Thread Starter
twoscooterz
Registered User
 
twoscooterz's Avatar
1986 CJ7 
 
Join Date: Oct 2010
Location: Eastsound
Posts: 109
Great information. Does anyone know if oil pan configuration is different and whether there will be clearance issues?

Thanks for all of your help so far.

'86 CJ7 Laredo, 258, Weber 38, DUI, T5 w/Hurst shifter, 4.56 Dana 30, AMC 20, Detroit TruTrac, Moser axles & Blue Torch truss, Dana 300, stock YJ springs SUA, 33" MTR's, Poison Spyder sliders, NewGen tank cover, Warn 9.5ti w/synthetic rope
twoscooterz is offline  
post #10 of 20 Old 10-17-2019, 07:43 AM Thread Starter
twoscooterz
Registered User
 
twoscooterz's Avatar
1986 CJ7 
 
Join Date: Oct 2010
Location: Eastsound
Posts: 109
Great information. Does anyone know if oil pan configuration is different and whether there will be clearance issues?

Thanks for all of your help so far.

'86 CJ7 Laredo, 258, Weber 38, DUI, T5 w/Hurst shifter, 4.56 Dana 30, AMC 20, Detroit TruTrac, Moser axles & Blue Torch truss, Dana 300, stock YJ springs SUA, 33" MTR's, Poison Spyder sliders, NewGen tank cover, Warn 9.5ti w/synthetic rope
twoscooterz is offline  
post #11 of 20 Old 10-17-2019, 04:17 PM
agear
Registered User
1984 CJ7 
 
Join Date: May 2011
Location: norfolk
Posts: 3,023
Quote:
Originally Posted by twoscooterz View Post
This might be a dumb inquiry....I recently discovered that I need to replace/rebuild my 258. I have a very limited budget. A buddy has a line on a rebuilt '74 (I think) 258 for $1k - block casting #3213867. I'm told it was a surplus fleet engine that was completely rebuilt and has been on the shelf for years. I need some help confirming whether it is a 1974 and whether it will bolt directly into my '86 CJ7? Wondering what works and more so, what won't work? My CJ has no emissions stuff and I've added an aluminum valve cover, Weber 38, DUI, and SS header - which I want to reuse. Will those parts, plus a stock intake, motor mounts, T-5, clutch etc bolt up? Aside from a small drop in HP and torque, any reason to not swap my '86 for an early 258? Will it "drive" differently? Good solution or bad idea? Thanks for any help.
What kind of fleet ?

1984 jeep cj7, 258 I6, rebuilt T176,rebuilt Dana 300, amc 20 , dana 30, 4.10's Trac-lok in rear , 4.10's detroit soft locker in dana 30, 2.5 inch bds suspension lift, 1 inch polyurethan body mount lift. Line ex. weber carburetor. factory tach. factory clock ,oem replacement speedomter cluster, and oil pressure gauge, factory volt gauge.
agear is offline  
post #12 of 20 Old 10-17-2019, 09:34 PM Thread Starter
twoscooterz
Registered User
 
twoscooterz's Avatar
1986 CJ7 
 
Join Date: Oct 2010
Location: Eastsound
Posts: 109
Quote:
Originally Posted by agear View Post
What kind of fleet ?
I'm not sure. My buddy did the deal on my behalf. Why do you ask? Red flags???

'86 CJ7 Laredo, 258, Weber 38, DUI, T5 w/Hurst shifter, 4.56 Dana 30, AMC 20, Detroit TruTrac, Moser axles & Blue Torch truss, Dana 300, stock YJ springs SUA, 33" MTR's, Poison Spyder sliders, NewGen tank cover, Warn 9.5ti w/synthetic rope
twoscooterz is offline  
post #13 of 20 Old 10-17-2019, 10:48 PM
agear
Registered User
1984 CJ7 
 
Join Date: May 2011
Location: norfolk
Posts: 3,023
Quote:
Originally Posted by twoscooterz View Post
Quote:
Originally Posted by agear View Post
What kind of fleet ?
I'm not sure. My buddy did the deal on my behalf. Why do you ask? Red flags???
I thought I saw something about postal jeep 258s not having the power of a regular 258

1984 jeep cj7, 258 I6, rebuilt T176,rebuilt Dana 300, amc 20 , dana 30, 4.10's Trac-lok in rear , 4.10's detroit soft locker in dana 30, 2.5 inch bds suspension lift, 1 inch polyurethan body mount lift. Line ex. weber carburetor. factory tach. factory clock ,oem replacement speedomter cluster, and oil pressure gauge, factory volt gauge.
agear is offline  
post #14 of 20 Old 10-17-2019, 11:07 PM Thread Starter
twoscooterz
Registered User
 
twoscooterz's Avatar
1986 CJ7 
 
Join Date: Oct 2010
Location: Eastsound
Posts: 109
Quote:
Originally Posted by agear View Post
I thought I saw something about postal jeep 258s not having the power of a regular 258
Well, that would suck. I saw a spec spreadsheet that indicates early 258's have a little less HP/Tq than the later ('86 in my case) variants. I will look into that. Do you recall where you saw that info? Thanks for the heads up!

'86 CJ7 Laredo, 258, Weber 38, DUI, T5 w/Hurst shifter, 4.56 Dana 30, AMC 20, Detroit TruTrac, Moser axles & Blue Torch truss, Dana 300, stock YJ springs SUA, 33" MTR's, Poison Spyder sliders, NewGen tank cover, Warn 9.5ti w/synthetic rope
twoscooterz is offline  
post #15 of 20 Old 10-18-2019, 02:17 PM
hp_lovecraft
Registered User
1981 CJ5 
 
Join Date: Sep 2009
Location: Maine
Posts: 1,342
AMC did a redesign on the 258 in 1980, to make it lighter and more efficient.
Engine swaps are so common, but most people don't give it a second thought until they go to replace a part and realize it doesnt fit right.

Its usually a failed valve cover gasket that makes people realize. But other odd things like water pumps spin reverse. Less important was the distro, intakes, exhauast carbs etc were usually different as well. Sensor mounts were different ie CTO etc. dip stick. I've done swaps in both directions and the main issue is usually emission components don't match up.... usually not something anyone really cares about
hp_lovecraft is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome