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Engine swap

Discussion in 'Jeep CJ' started by Jeep Newby, May 14, 2017.

  1. May 14, 2017 at 7:51 PM
    #1
    Jeep Newby

    Jeep Newby [OP] Member

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    Looking for some suggestions. Running an inline 4.2 with 5 speed transmission. Can i swap out to a 360 and use the same transmission or do i need to replace everything? Also, is a 360 the way to go. Positives and negatives please. Wad thinking about a 304 but have heard some poor reviews.
     
  2. May 14, 2017 at 7:59 PM
    #2
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

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    Subbed. I think the 360 would rock a CJ
     
  3. May 15, 2017 at 7:26 AM
    #3
    OFFGRID

    OFFGRID Well-Known Member

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    Houston
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    1979 Jeep CJ7, 258, TH350, NP208
    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    Yep I agree, the 360 would be nice. You might consider a Chevy 350 install. They are cheaper and easier to install, and they have a bigger aftermarket pool. Read everything Novak adapters has in their research section about motors, motor swaps, and transmission adapters. It might be that you cannot get an adapter to make the 360 work. Maybe you'll get lucky and it will bolt right up (doubt it). I'm pretty sure they make an adapter for the Chevy motor. Novak will have all of these answers and what products they make. If Novak doesn't make the 360 to 5 spd adapter you might check Advanced Adapters.

    https://www.novak-adapt.com/knowledge/engines/about/dodge/mopar-small-block/
     
    chris4x4 likes this.
  4. May 16, 2017 at 5:59 AM
    #4
    Jeep Newby

    Jeep Newby [OP] Member

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    Awesome. Thank you. I'll check into it. Guessing I'll need a small block?
     
  5. May 16, 2017 at 6:22 AM
    #5
    OFFGRID

    OFFGRID Well-Known Member

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    Houston
    Vehicle:
    1979 Jeep CJ7, 258, TH350, NP208
    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
  6. May 16, 2017 at 7:14 AM
    #6
    OFFGRID

    OFFGRID Well-Known Member

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    First Name:
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    Houston
    Vehicle:
    1979 Jeep CJ7, 258, TH350, NP208
    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    Id like to go back to your original question. The V8 is always a great option, but I'm partial to the old school 4.2L or 258 as it used to be called. The 258 can easily make 350HP and 400+ft/lbs of torque. It was banned from the drag strip I think back in the 60s, because nothing could get close. I run the extreme offroad cam from comp cams, with header and Howell TBI which was barrowed from the late 80s chevy 350. The 2 barrel factory intake is the best on the market for the Howell TBI because it is a dual plane creating more low end power. I say this because there are may 1 barrel intakes out there. Ofi's I believe are single plane, not really good for jeeping and were designed more the the AMC hornet and javelin which also ran the 258.

    I have been playing with the idea of running a Fitech TBI with a Clifford 4 barrel Intake. I feel like the howell TBI is not giving me enough juice.
     
  7. May 16, 2017 at 7:32 AM
    #7
    Jeep Newby

    Jeep Newby [OP] Member

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    Running a 4.2 with a 2 barrel and just have no power on highway at all. Can barely get to 70
     
  8. May 16, 2017 at 8:58 AM
    #8
    OFFGRID

    OFFGRID Well-Known Member

    Joined:
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    First Name:
    Peter
    Houston
    Vehicle:
    1979 Jeep CJ7, 258, TH350, NP208
    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    My buddy just installed a similar setup except that he is running a carb (motorcraft 2100), not TBI and he also has the OEM ex-manifold, but he did install an extreme off-road cam. He ran well before the rebuild. He did not like going over 60-65 because he was 3500 rpm at 65mph with his 33s and 410 gears, but he had the power to get there. 258s redline around 5000rpm, but they sure feel like they are coming apart at 3500. I have 4.56 gears and 37s and with the T150 could do 75 at 3000ish rpm.

    Your issues, do you still have the Cat in your exhaust. It may be clogged. Do you still have the smog stuff on your jeep. This stuff is very power robbing especially if it hasn't been maintained over the years. It is near impossible to find all the parts to maintain it so most take it out and remove the bbd carb and run the motorcraft 2100 carb. I believe Summit sells the adapter kit. What is your gearing, 3.07? Looks like you have good sized tire too. Do you have the T150 3 spd? One more question. Is your speedo correct?

    The 70s CJs were only designed to cruise at 55mph. This is the sweetspot for the 258/T150. You really need an overdrive to go 70 for extended periods. You might look into an over/under drive setup http://hermtheoverdriveguy.com/overdrive-types-2 , or think about swapping in a 5spd refer back to Novak adapters.

    You really can't go wrong no matter how you build your jeep. Jeeps are just plain cool whether you have the small block 454 or the old 2.5 Iron duke.
     
    JEEP # 5 likes this.
  9. May 16, 2017 at 2:03 PM
    #9
    Jeep Newby

    Jeep Newby [OP] Member

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    Love the response however I'm new to jeeping. Not a mechanic by any means but learning slowly as i fix things. Its a five speed.
     
  10. May 16, 2017 at 3:16 PM
    #10
    JEEP # 5

    JEEP # 5 Well-Known Member

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    Has 35 X 17 X 12 LT & a 4" RC lift, Smitty Bilt Nerf bars 3" tube

    Mr Newby,

    If you have the money to convert to V-8. Do it is my recommendation. OffGrid really knows his stuff. I can confirm there is much to be said about how frustrating it can be driving a 4 banger and just trying to stay up with folks on the freeway. Even a healthy Iron Duke for me only would do 60 MPH peddle to the metal. Eventually the Duke gave out from overheating. (Keep in mind my wife drove it for a 30 minute freeway commute in California where no one travels at 55). So she drove it hard and it lasted maybe a couple years before those hard driven miles started to kill it.

    Having had a few jeeps of my own, I have always been jealous of those V-8 guys just in IDLE climbing around stuff that my other CJ5 with the 258 six would have to work at. Here is the thing, If you have (V-8) even stocker small block the vehicle will crawl over anything with stock gearing with-in reason. You can add tall tires and she'll do great. It's a V-8!!

    Reminds me of my 55 Willy's Truck. Took out the Inline 4 banger, put in a AMC Javelin 290 V-8 using a Hornet Bell housing to a T-10 Ford manual trans, kept it stock with the 2 brl carb. You could stand a nickel on its edge on the air cleaner at idle. Added more leafs to the springs and some hardware store clamps to hold them. Transfer case stayed in just fine and it came with a PTO winch that ran off the motor. That thing would run and had the power to climb anything with the stock 4:88 gears. Revved a bit on the highway but who cared the V-8 was out of a junker Javelin. Awesome times!!

    If you find the coin to V-8. Do it. Probably the Stock SB Chev conversion kits mentioned by OffGrid would be excellent starting point. This Forum is the best resource for help as you can tell.
     
  11. May 17, 2017 at 6:41 AM
    #11
    OFFGRID

    OFFGRID Well-Known Member

    Joined:
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    Member:
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    Messages:
    2,018
    Gender:
    Male
    First Name:
    Peter
    Houston
    Vehicle:
    1979 Jeep CJ7, 258, TH350, NP208
    Howell fuel injection, header, HEI distributor, TH350, NP208, SOA lift with YJ springs in the front & GW springs in the Rear. AMC20 with G2 1 piece chromos trussed, Dana 30 with G2 chromos and 760x ujoints and MM Stainless Hubs, Geared 4.56. Tom Woods shafts, Metal cloaks, Caged, 37" Toyo MTs.
    Do you Know what 5 speed you have, AX5 or AX15 maybe. Novak's website will tell you how to tell the difference. The 79 CJ did not come with a 5sp; only a 3spd and a 4 spd. Can you look between the bell housing and the engine block and see if there is a metal adapter plate about 1/2 inch thick. Do you have one?
     
  12. May 30, 2017 at 7:42 PM
    #12
    Jeep Newby

    Jeep Newby [OP] Member

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    Haven't checked yet but will let you know asap. Thanks
     

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