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304 engine questions

Discussion in 'CJ' started by Duff, Apr 20, 2020.

  1. Apr 20, 2020 at 5:23 AM
    #1
    Duff

    Duff [OP] Well-Known Member

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    Yesterday, I bought a rebuilt 304 from a friend that has abandoned his CJ7 project, I got everything except a bell housing and flywheel. Will the bell housing that's behind my 258 work on the 304? Also, any recommendations on chassis long tube or shorty style headers?
     
  2. Apr 26, 2020 at 8:05 AM
    #2
    Duff

    Duff [OP] Well-Known Member

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    Picking up the 304 at noon today, going to install as soon as the 258 sells. Still waiting on the lift, but here's some other stuff that arrived. I'll post a picture after I get everything bolted up.

    Jeep Suspension.jpg
     
  3. Apr 26, 2020 at 12:29 PM
    #3
    Duff

    Duff [OP] Well-Known Member

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    Finally got it home, fully rebuilt, never started, 304, comp cam, roller rockers etc..

    Jeep Engine.jpg
     
    Last edited: May 3, 2020
    chris4x4 and aggrex like this.
  4. Apr 27, 2020 at 5:12 PM
    #4
    Duff

    Duff [OP] Well-Known Member

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    Looks like bell housing's the same, no luck in finding a good used 304 flywheel, so looking at new on that.
     
    Last edited: May 3, 2020
  5. May 25, 2020 at 7:13 AM
    #5
    Duff

    Duff [OP] Well-Known Member

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    Lift kit is done and also pulled the 258 today, gonna prep the engine bay for the 304 and hopefully install it soon.

    JeepEngineOut2.jpg
    JeepEngineOut1.jpg
     
    aggrex likes this.
  6. May 25, 2020 at 5:56 PM
    #6
    Jim Beam

    Jim Beam Well-Known Member

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    Duff, this would be a good time to check the frame for cracks. Common places for cracks would be at each corner of the winch mounting pad, the front spring shackle clearance hole, and the lower part of the frame just before the main pivots on the front springs, especially when a tall lift kit has been installed.
     
  7. May 25, 2020 at 7:12 PM
    #7
    Duff

    Duff [OP] Well-Known Member

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    Yes, going to take it to the car wash and blast the frame / chassis and under body, hopefully will have some metal left. After that going to paint the frame from firewall forward and undercoat the rest back. Thanks for the tip, I'll check for cracks. I did notice the DS frame horn is about a half inch off from lining up with the new front spring bushing, I'll get that a little closer too.
     
  8. Jun 29, 2020 at 12:31 AM
    #8
    Eyy-sp12

    Eyy-sp12 Active Member

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    T-176 Transmission with Dana 300
     
  9. Jun 29, 2020 at 12:37 AM
    #9
    Eyy-sp12

    Eyy-sp12 Active Member

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    Have you got your engine installed? Was wanting to ask did you get good gains . I've got a 304 was wanting to make more power . Some have told me just to get a 360 . I like my 304 I just don't know a lot about building motors . I'm a great mechanic but have only repaired engines to stock . Was going to see if you were happy with the new engine and ug . What cam lift did you use , also intake , and carb . Wanting to squeeze more power out of mine . Any info would be great . Thank you
     
  10. Jun 29, 2020 at 4:10 AM
    #10
    Duff

    Duff [OP] Well-Known Member

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    A guy stopped by the shop as I was getting the engine ready for install and he ended up buying my Jeep! I used to own a 1979 CJ 7 with a factory 304, pretty much stock, it had headers and I THINK a 2bbl carb. It ran great and had plenty of power!
     
  11. Jun 29, 2020 at 6:06 AM
    #11
    Eyy-sp12

    Eyy-sp12 Active Member

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    Thanks for writing me back . Yeah mines a 77 it runs great. I was just trying to make it stronger . Like I said people have told me just get 360 . I don't need that . I would like to just put a good lift cam in it. I know if I do I need to try and match it to the intake . Then get a carb that will be big enough to give it enough fuel . I think a 4 barrel 600 cfm carb would do it .
     
  12. Jun 29, 2020 at 6:15 PM
    #12
    Duff

    Duff [OP] Well-Known Member

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    I was going with a Holley 600 vac secondary and fender well headers. Good luck with your 304!!!
     
  13. Jul 1, 2020 at 10:17 PM
    #13
    Eyy-sp12

    Eyy-sp12 Active Member

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    Thanks good luck on yours as well.
     
  14. Oct 5, 2020 at 8:02 AM
    #14
    Speedsac

    Speedsac New Member

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    Duff, what modification are needed to run the fender well headers? Will they clear the footwells of the tub without cutting? I've never seen them on a Cj unless I just didn't know they were there.
     
  15. Oct 5, 2020 at 6:16 PM
    #15
    Duff

    Duff [OP] Well-Known Member

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    I sold my CJ project before I got the headers installed, but I had talked with a friend on mine that owns a CJ 5 with FW headers. Going from memory, he said he did some very minor trimming on the inner fender and I THINK he removed the steering shaft before installing the Hedmans.
     
  16. Oct 6, 2020 at 4:47 PM
    #16
    Speedsac

    Speedsac New Member

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    Great and thanks for the info. The set I have are Hooker, I'll assume they fit as good as any reputable maker.
     
  17. Jan 18, 2023 at 7:36 AM
    #17
    churchilldavid

    churchilldavid New Member

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    Possibly, the the bell housing behind your 258 may work on the 304, but I recommend checking with a professional or doing some research to be sure. The same goes for the flywheel, as the 304 may have different specifications than the 258.
    As for headers, it depends on your specific build and what you're looking for. Long tube headers can provide more power and a deeper exhaust tone, but they can also be more difficult to install and may not fit as well in certain vehicles. Shorty headers are typically easier to install and may fit better in certain vehicles, but they may not provide as much power.
    Also, I suggest you to use c15 acert delete kit as it will help you to improve the performance of your engine.
     
    Last edited: Jan 26, 2023
  18. Jan 18, 2023 at 10:02 AM
    #18
    LYFZGOOD

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    FYI on the bottom of each post is a date of when it was posted. But good information for future jeeper. Thanks.
     
  19. Jan 28, 2023 at 8:20 AM
    #19
    PapaCJ5

    PapaCJ5 New Member

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    So I have a rebuilt 304 and I’m having trouble maintaining oil pressure ( or at least that is what the oil pressure gauge is saying). I have replaced the gauge and still getting same issue. I heard there maybe a spring issue in the oil filter bypass issue. Not hearing any lifter issues or other problems related to low oil pressure. Haven’t pulled a valve cover to make sure it is oiling. Thoughts
     
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