1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

225 odd fire vs. 258

Discussion in 'Intermediate CJ-5/6/7/8' started by grog420, Jul 17, 2008.

  1. Jul 17, 2008
    grog420

    grog420 New Member

    redding ca.
    Joined:
    Jul 29, 2006
    Messages:
    35
    Cracked block in my 258 and was looking for a replacement engine , I was wondering horse power and torque diffrences in the 225 odd fire and the 258?
     
    grog420, Jul 17, 2008
    #1
  2. Jul 17, 2008
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
    Don't even consider it. There's nothing magic about the 225, other than it fits the Jeep engine compartment wonderfully well. It has a heavy flywheel, which makes the low-speed performance feel very strong. The pre-81 258 is heavily counterweighted, so I expect it will have the same SOTP (seat of the pants) feel as the 225.

    If you compare HP and torque of the two, the 258 has to be the winner... 15% more displacement. Power is roughly proportional to displacement. Be sure to compare specs from the same era; in 1970 or 1971, the way HP is measured was changed (gross to net) so numbers across that boundary are not comparable.

    JMO - if you want more power, go with a 4.0L, not a 225. That will give you a lot more power than the 225 and be a comparatively easy and hassle-free swap. There's even a forum dedicated just to the 4.0L swap... let me see if I can find it.
     
    timgr, Jul 17, 2008
    #2
  3. Jul 17, 2008
    sparky

    sparky Sandgroper Staff Member Founder

    Perth, WA
    Joined:
    Sep 20, 2002
    Messages:
    9,221
    Too much effort like Tim said. Go with a 4.0 or better stroke a 4.0 block.
     
    sparky, Jul 17, 2008
    #3
  4. Jul 17, 2008
    Desert Storm

    Desert Storm FNG

    PHoenix Az.
    Joined:
    Oct 17, 2007
    Messages:
    74
    You should see the 258 go up the dunes in Arizona ! some headers and carter carb setups just fly !
     
    Desert Storm, Jul 17, 2008
    #4
  5. Jul 17, 2008
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
    timgr, Jul 17, 2008
    #5
  6. Jul 17, 2008
    Desert Storm

    Desert Storm FNG

    PHoenix Az.
    Joined:
    Oct 17, 2007
    Messages:
    74
    Great Post ,,,, might have to build a 4.0 jeep now !
     
    Desert Storm, Jul 17, 2008
    #6
  7. Jul 20, 2008
    Boodie

    Boodie Boodie

    TOLEDO, OHIO
    Joined:
    Jul 4, 2006
    Messages:
    95
    I took the best of both worlds.....258 with a 4.0 HO head (timgr knows the casting #)!!!! Vrooooom!!! I kept my intake (yes, carter carb too) and get MORE HP and 24MPG!!!!! Of course I get better gas mileage at 60mph or less.

    I have a brief writeup about it here in the buid section: http://earlycj5.com/forums/showthread.php?t=53136

    4.0 HO Head on the 258:

    [​IMG]


    Mine is a budget rig it case anyone was wondering why I took this route.

    Just my 2 cents! :D

    ~Boodie
     
    Last edited: Jul 20, 2008
    Boodie, Jul 20, 2008
    #7
  8. Jul 20, 2008
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    23,596
    My notes say casting # 7120. You want the HO head, 1991 and newer.
     
    timgr, Jul 20, 2008
    #8
  9. Jul 20, 2008
    Boodie

    Boodie Boodie

    TOLEDO, OHIO
    Joined:
    Jul 4, 2006
    Messages:
    95
    Yep, that's the one! I knew timgr would know!

    :tea:
     
    Boodie, Jul 20, 2008
    #9
New Posts