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 HEI Clarification

Discussion in 'Early CJ5 and CJ6 Tech' started by PostaljeepSS, Jul 19, 2008.

  1. Jul 19, 2008
    PostaljeepSS

    PostaljeepSS Member

    Boise,ID
    Joined:
    Jun 22, 2008
    Messages:
    86
    I've read the HEI info in the "other V6 links" and it explains how it works very well but I think I'm just missing something obvious. They mention the GM HEI but the only GM HEI I'm aware of is for a V8. Is there a V6 specific model compatible with the 225 or is it some conversion for the 225 distributor? It's a slow weekend and this might make a nice project to get done. Any info would be great!
     
    PostaljeepSS, Jul 19, 2008
    #1
  2. Jul 19, 2008
    sparky

    sparky Sandgroper Staff Member Founder

    Perth, WA
    Joined:
    Sep 20, 2002
    Messages:
    9,221
    Buick 231 HEIs are what are used.

    See the tech section links for more on ID and conversion. The third link has information on an even fire conversion if that's what you'd like to do, but I'd just skip it and buy an odd-fire HEI from the parts store.

    Plenty of information in the forum here too about the conversion.

    *edit* Added distributors to the 225/231 parts interchange guide. Glaring oversight on my part!
    http://earlycj5.com/tech/engines/225/225-231InterchangeGuide.php
     
    Last edited: Jul 19, 2008
    sparky, Jul 19, 2008
    #2
  3. Jul 19, 2008
    PostaljeepSS

    PostaljeepSS Member

    Boise,ID
    Joined:
    Jun 22, 2008
    Messages:
    86
    EXCELLENT! So if I understand correctly a 231 oddfire HEI will drop in and work perfectly and a 1975 Buick Apollo with a 231 or 3.8L engine would tell the parts store guy what I need? If so I'm ready to get this thing going :)
     
    PostaljeepSS, Jul 19, 2008
    #3
  4. Jul 19, 2008
    sparky

    sparky Sandgroper Staff Member Founder

    Perth, WA
    Joined:
    Sep 20, 2002
    Messages:
    9,221
    Yes, just follow the conversion process outlined in those links. You'll have some grinding on the intake and some rewiring to bypass the ballast resistor.
     
    sparky, Jul 19, 2008
    #4
  5. Jul 19, 2008
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
    Messages:
    12,530
    That's correct. You may need to grind on the left front corner of the intake manifold for clearance and use a button head bolt in that corner. This is all covered in the tech section.
     
    nickmil, Jul 19, 2008
    #5
  6. Jul 19, 2008
    Rex Garnes

    Rex Garnes New Member

    Murrieta Ca and...
    Joined:
    Jul 18, 2008
    Messages:
    2
    You can obtain one for the 225 at CRTperformance.com
     
    Rex Garnes, Jul 19, 2008
    #6
  7. Jul 21, 2008
    jeep67

    jeep67 Member

    Shasta, Ca
    Joined:
    Dec 11, 2006
    Messages:
    205
    You will also find that you will need to get the smallest vac. advance you can and clock the distributor to the side to provide enough clearence from the fan blades. You may also need to add a spacer to the fan for additonal clearence. This will all likely depend if you are running items, such as a power steering pump.
     
    jeep67, Jul 21, 2008
    #7
  8. Jul 21, 2008
    gte636p

    gte636p Member

    smyrna, Ga
    Joined:
    Sep 23, 2002
    Messages:
    492
    I'm currently not running a vacume advance. I know it will help with power, but how much will be gained by putting it in?
     
    gte636p, Jul 21, 2008
    #8
  9. Jul 21, 2008
    jeep67

    jeep67 Member

    Shasta, Ca
    Joined:
    Dec 11, 2006
    Messages:
    205
    That is a good question, one that I can't answer since I have never ran without having a vac. advance. I suspect, however, that you will find that you will get better fuel mileage, if not more power.

    When I did my HEI swap, I replaced the bulky vac. advance unit with one that matched the same throw, but was quite a bit smaller. There is only about 1/4 of clearance between it and the the fan blade. Fortunately, when under load, or if I swamp the moter in water, the fan will pull away from the vac. advance unit, towards the radiator.

    Good luck.
     
    jeep67, Jul 21, 2008
    #9
  10. Jul 21, 2008
    sparky

    sparky Sandgroper Staff Member Founder

    Perth, WA
    Joined:
    Sep 20, 2002
    Messages:
    9,221
    Vacuum advance is mainly for fuel economy, doesn't help performance.

    See Rich Mott's article linked from the Tech Library for more.

    I've a Crane adjustable unit on mine.
     
    sparky, Jul 21, 2008
    #10
New Posts