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304 Vs. 258 Advantages

Discussion in 'Intermediate CJ-5/6/7/8' started by Everett Reed, Nov 28, 2018.

  1. Nov 30, 2018
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
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    Amc 360...cheaper better than those other two option. Combine the 360 with a granny t18 and you will have the better set-up for pavevement and off-road.
     
  2. Nov 30, 2018
    Chilly

    Chilly Active Member 2019 Sponsor

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    A 360 that he doesnt own, coupled to a T18 that he doesnt own via a $500 adapter, then coupled to a t-case through another $500 adapter is cheaper how?
     
  3. Nov 30, 2018
    rejeep

    rejeep Well-Known Member Sponsor 2019 Sponsor

    Rochester, NY
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    360 and T18 is a native match...
    A 304 becomes a 360 fairly easy if rebuilding..
     
  4. Nov 30, 2018
    GeorgiaFlattie

    GeorgiaFlattie Member

    Canton, GA
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    Feb 9, 2017
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    If he can find a CJ T-18. The FSJ T-18s have much longer input shafts making them too long for a CJ.
     
  5. Nov 30, 2018
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
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    He said he was going to rebuit the 304. For having been throught the process some time ago i was given a rebuilt price around 400$ lower for the same part on the 360 over the 304. i found up a 360 in a junkyard and bought it for 50$. So i just saved there 350 buck for a engine with better specs.

    As for t18...i found two short granny t18 around the junkyard here and paid around 200$ for each of them. As for transfert case a dana 20 will bolt right there since all jeep cj t18 had a dana 20.
     
  6. Nov 30, 2018
    Chilly

    Chilly Active Member 2019 Sponsor

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    A Jeep T18 will bolt up to a Dana 20 (pretty sure all Jeep D20 are same but not even 100% on that), but thats a rare and expensive T18. All other commonly available T18 will require a $500 adapter to fit the 360, and another $500 adapter to attach the D20.

    I dont know why a 360 rebuild was $400 cheaper unless you asked for higher CR pistons. There are no off the shelf high CR pistons for a 304 but there are for the 360. But other than that parts price and machining costs are identical.
     
  7. Nov 30, 2018
    Keys5a

    Keys5a Sponsor Sponsor

    Florida Keys
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    Everett already has both a 258 and a 304, with the option of rebuilding either. If it were my choice, there would be no debate. The 304 all day long. Its a tough durable engine like the 258, but can easily produce more power and torque, and is not much more cost to rebuild. If you have a transmission that can handle a bit more power, go with the 304. Consider a torque cam like the Melling MTA-1 and an alloy Edelbrock 4 bbl manifold with a 500cfm or smaller carb. This combination will make a very satifying swap for your Jeep.
    -Donny
     
    Last edited: Dec 3, 2018
    rejeep likes this.
  8. Dec 1, 2018
    sterlclan

    sterlclan Member Sponsor

    exploring the...
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    plus it sounds better...if you haven't driven a v8 cj I recommend doing so . ear to ear smiles will result.
     
    JB47 likes this.
  9. Dec 1, 2018
    Chilly

    Chilly Active Member 2019 Sponsor

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    I will say this about rebuilding a 304 vs a 360. If you can be OK with a mild built 304 and do not yearn for lots of power then a 304 will serve you well. If you want more power then skip the 304 and go with a 360. It takes a lot of money to make a 304 approach a stock 360, and it will not have the reliability of a stock 360. Youll need a radical cam, powerful spring that are hard on valve seats, etc.
     
  10. Dec 3, 2018
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
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    Just got this on facebook

    Matt Rutland
    49 minutes

    T-18/dana 20
    $850
    Rome, GA
    T-18
    Dana 20 t-case
    Includes shifters and bellhousing
    13-01 granny first


    Not so rare, and i wasnt searching for it....
     
  11. Dec 3, 2018
    Chilly

    Chilly Active Member 2019 Sponsor

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    If its not rare then the price is 2X market for a 4sp and a dana 20 (they're giving away D20 on this very forum)
     
  12. Dec 3, 2018
    Daryl

    Daryl Sponsor Sponsor

    Bonney Lake, WA
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    A J truck T18 and a 20 has very little value. Yes I have given one away before bolted up to a running 360(not sure why anybody would want an AMC motor). A 77-79 CJ T-18 is worth about $500 though. The devil is always in the details.
     
  13. Dec 3, 2018
    IrishCJ6

    IrishCJ6 Member

    Wicklow Ireland
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    Dec 6, 2010
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    If you can find a T18 out of an I6 engined vehicle it will fit, I've just done this install in my CJ6, yes mine is longer than a 5 but there is still plenty of length for a drive shaft. The bellhousing is the same as a T15 with only a 1" adapter plate.
     
  14. Dec 4, 2018
    wally

    wally SSSSTER

    upper merrimack...
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    cheaper in canadian dollars?
     
  15. Dec 4, 2018
    wally

    wally SSSSTER

    upper merrimack...
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    we get that you don't like amc motors. this is the intermediates section, and those came with amc motors. zip it.
     
  16. Dec 4, 2018
    Jrobz23

    Jrobz23 Member

    Northern, WI
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    258 - nothing beats an AMC I6

    There is just so much right about that engine in a Jeep.

    Keep the T14. Run it. Enjoy it. These vehicles are smile factories.
     
  17. Dec 5, 2018
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
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    I do wheel with people who have the Amc I6....i can say there no one near the versability of my amc V8 ;)
     
  18. Dec 5, 2018
    Jrobz23

    Jrobz23 Member

    Northern, WI
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    For my usage, the lower TQ peak is more useful than some more top end power. If you have dunes and stuff, I can see a healthy V8 to rip up them, definitely. Also, seeing the mods to your Jeep, I can see why you'd want a V8. That's a neat Jeep.

    AMC V8s are definitely neat motors, and sound AWESOME, but I guess I like the low end over the high end, and just plain like an old school inline engine. Feels right to me somehow. Maybe it's just my area and experience, but it seems like upping the power on a I6 uses WAY less niche aftermarket vendors/parts these days. You have 14 more years of high volume to draw from, I guess. Once you talk about modified engines, though, both can be built for whatever you want. In all honesty, those 70s Jeeps need more gearing than anything. All the engine choices in the 70s were great IMO, but most of the gear ratios were terrible.

    The OP is prolly best suited to run whatever motor is in better condition and matches the rest of the chassis as it sits. Use your best parts and pick which route requires the least amount of (re)engineering.
     
  19. Dec 6, 2018
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
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    Good point there, i may have forgot to tell that when rebuilding the amc 360 i did ask for a low end torque cam, that make a good difference.
     
  20. Jan 8, 2019
    73cj5

    73cj5 Member

    NH
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    I would vote for the 258 due to it being a direct bolt in. Swaps will nickel and dime you to death.
     
    Jrobz23 likes this.

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