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350 Chevy

Discussion in 'Intermediate CJ-5/6/7/8' started by Allan, Jan 2, 2020.

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  1. Jan 2, 2020
    Allan

    Allan Member

    Olympia
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    How difficult would it be to swap out the 304 amc for the Chevy 350, 1974 Jeep renagade I have a t-15 transmission! How difficult are the mods?
     
  2. Jan 2, 2020
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

    Medford Mass USA
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    Uhhh, you can do it. Not sure about the mounts - it would be straightforward if you can weld. Novak will sell you an adapter. Some plumbing and wiring to move around.

    I kinda think "why?" but it's up to you. The most bang-for-the-buck IMO is to swap in an AMC 360. Big power boost for little money, and just drops in. The 360 has better heads (bigger valves) and more displacement than a 304, and is not expensive/exotic/delicate like the 401. Plain iron block that can easily go 60 over. And there are a lot of them compared to the 401. A (steel!) 401 crank in a 360 block will give 396cid at 60 over - but you'll need custom pistons to get the right deck height.

    The T-15 is strong, fine for either motor. It was the standard transmission in 4V 360 Wagoneers and J10s through 1979, and did fine. Pretty sure you'll break an axle first. No burnouts! :n:
     
    Last edited: Jan 2, 2020
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  3. Jan 3, 2020
    colojeepguy

    colojeepguy Colorado Springs 2019 Sponsor

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    Intermediate CJ had a 30 spline Dana 44 with 1 piece axles....it should be OK unless seriously abused.
    There's good arguments both pro and con for this swap...the points that Tim makes are all good ones, but the Chev is cheaper, more plentiful and easier to build....either one would make for a fun Jeep! ;)
     
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  4. Jan 3, 2020
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

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    Wondering - why is the Chevy any easier to build? They are both generic American V8s. Any machine shop that can work on a Chevy can work on an AMC engine. Any shadtree mechanic that can build a Chevy can build an AMC. Each engine has its strong and weak points. I could understand wanting a modern Chevy V8 for mileage etc. but I predict it would take a long time to make back the investment in a Vortec-era Chevy, and you pretty much have to go with the native MPI to retain any of that modern effiiency.

    Personally I think the 304 is plenty of engine for that chassis, and it has the potential for quite a lot more power without any heroic mods. The 360 is appealing because it's quite a bit more powerful than the 304 without any mods, and it and the 304 respond very well to mild improvements in compression, intake, cam and exhaust . So would the Chevy, but I don't see why that engine would be any easier to enhance than the AMC. Standard stuff for both.

    Adapting the Chevrolet & GM Standard Shift Bellhousings to the Jeep CJ & FSJ Borg-Warner T14, T15 & T18 Transmissions
     
    Last edited: Jan 3, 2020
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  5. Jan 3, 2020
    sterlclan

    sterlclan Member

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    The Chevy is easier to source parts and there are more choices as to hot rod parts. That said I’d stick to an amc it fits without any adaptation.
     
  6. Jan 3, 2020
    duffer

    duffer Rodent Power 2019 Sponsor

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    Actually, orders of magnitude more parts available for the sbc. Every part. And way cheaper. My experience with the 360 was that there just isn't ANY cure for the abysmal efficiency of that engine. I never could coax the mileage above the low teens. If you put together a 350 with the right parts, 18 mpg is pretty easy.

    However, the 360 is certainly the path of least resistance. And assuming you find one that doesn't need a complete rebuild, no doubt cheaper.
     
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  7. Jan 3, 2020
    mrtii

    mrtii 1972 cj51986 cj7 2020 Sponsor 2019 Sponsor

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    i would second timgr regarding everything he said and only add look to throttle body injection kit would improve this engine a lot in all areas of the driving experience for that chassis
     
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  8. Jan 3, 2020
    Allan

    Allan Member

    Olympia
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    Interesting, never knew that was an option
     
  9. Jan 3, 2020
    45es

    45es Member 2019 Sponsor

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    Isn't that another reason to go with the Chevy 350 engine? Throttle body fuel injection is native to the engine and can be found everywhere.
     
  10. Jan 3, 2020
    zila

    zila I throw poop

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    TBI is readily available for the 304. Either a JY conversion or a kit to convert. I have TBI in my 304. Beats the OEM carb deal by 500% at least.
     
    Last edited: Jan 3, 2020
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  11. Jan 3, 2020
    Ohiowrangler

    Ohiowrangler New Member 2020 Sponsor

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    To play devils advocate. I've done several SBC conversions, If I had a CJ that was worthier trying to keep original, I'd keep the 304. I have 12 years GM dealership experience, My YJ is SBC powered. My current project consists of 3 piles of parts(more later). It's going to have a 4.3 or a 350. To keep the jeep thing alive, I'd keep the 304. Just my opinion, Ron
     
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  12. Jan 3, 2020
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

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    If you want native TBI, the Chevy has that and AMC does not. However, several aftermarket suppliers will sell you a bolt-on kit for the AMC engines that uses the GM Rochester hardware and is customized to the AMC engine. With some computer saavy, it's not that difficult to tune a junkyard system to work on an AMC engine either. There are other DIY options too, like the Megasquirt computer. And several aftermarket sellers offer a turnkey universal kit that tunes itself to the target engine. TBI is far from unavailable for the AMC engines.
     
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  13. Jan 3, 2020
    Allan

    Allan Member

    Olympia
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    So which one did you use and how much gas saving and performance do you think you attained from the conversion?
     
  14. Jan 3, 2020
    sterlclan

    sterlclan Member

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    its a jeep, its like pushing a brick down the road,its about smiles per not miles per...
     
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  15. Jan 4, 2020
    Zoomer

    Zoomer eJeeper (walking) 2020 Sponsor

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    So why are you wanting to swap out your engine and why are you asking specifically about SBC? What are you trying to accomplish?
     
  16. Jan 4, 2020
    zila

    zila I throw poop

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    I got mine from Affordable TBI. BUT, if I knew then what I know now, I'd buy Hamilton. Affordable has zero customer support. When I had issues Hamilton helped me out.
     
  17. Jan 4, 2020
    Allan

    Allan Member

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    I’m not sure, just looking at options
     
  18. Feb 20, 2020
    kmolles

    kmolles New Member

    Sebastopol, CA
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    I have a 1973 CJ5 with an AMC 360 that has a cam, headers, HEI and a Fitech injection system. It runs good, but I am building a SBC 350 right now. I cut my teeth on SBC motors and can get them to run well and somewhat efficient. Plus, part selection is fantastic. I know it's all a matter of preference. I'm not saying one is better than the other, I just strongly prefer the SBC.
     
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  19. Mar 3, 2020
    BadGoat

    BadGoat How High Can You Climb?

    St Croix, USVI
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    The Holley Sniper is probably the most common bolt on TBI conversion available today and can be put on any motor with a 4 barrel style intake. I have one on my 351C in my pickup and it makes it a much nicer daily driver. One turn of the key and it fires up and settles down. The do not make more horsepower then a well tuned carburetor and the mileage is only a little better. Driveability is where the real benefit comes in. FiTech is probably a close second, and the rest are all specialist suppliers. All of the modern TBI kits require upgrading the fuel system to handle higher pressure and installing at least 1 O2 sensor. More advanced kits will also control your engine timing and your electric fans. There are additional options for controlling Nitrous or working with superchargers and turbos, if you want to build something on the wild side.

    Mike
     
  20. Mar 3, 2020
    kmolles

    kmolles New Member

    Sebastopol, CA
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    Yes, my Fitech will control my timing, although I currently don't have it doing so. It running the electric fans is nice. If I purchase another unit, it'll probably be the Holley. The fuel delivery system (with return) was installed to handle the extra flow and pressure (58 psi)
     

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