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Big Block Time!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by militaryblazer, Jan 26, 2001.

  1. militaryblazer

    militaryblazer 1/2 ton status

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    Well I have found a 454 for sale. It is currently in a jeep j10 that is junk. The engine is supposed to be a crate motor with probably around 20k miles on it. If I get the number off of it can I find info about it from GM? What all would be involved in putting it in my blazer. My blazer has a diesel and th400. The tranny in the jeep is also a th400. Would I need new motor mounts and the engine should bolt up to my th400 right? The engine starts very good and runs real smooth. It currently has stock exhaust on it! I will have more questions about my axles later on but if anybody could help me with my questions so far it would help alot! Thanks!

    [​IMG]See more--&gt;<A target="_blank" HREF=http://www.geocities.com/m1009_86>http://www.geocities.com/m1009_86</A>
     
  2. ut77gmc

    ut77gmc Registered Member

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    I swapped my 402 in place of my 350 with the same small block mounts. I'm not real sure of the Jeep T-400 bolt pattern, but I'm sure it will bolt right up to your existing tranny. (I think you'll want a different stall converter, though. Diesel engines make a lot more low end than any gas engine).

    You're going to have some swapping of accessory parts for the diesel/gas conversion.

    Congrats on the acquisition. Let me know if you want to give me those axles out of the J10 also. They'd work real well under my XJ.

    '77 GMC K15 LWB.....likes to get muddy
     
  3. Shawn

    Shawn 1/2 ton status Premium Member Author

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    Find the casting # on the heads (under valve covers). Some heads will limit the potential of a BBC. I'm not sure if it bolt up to your Diesels 400 trans. I thought diesels had a BOP bellhousing but I could be wrong. I'd get new motor mounts for a 80's 3/4 ton with 454.

    Shawn
    87 K5
    few mods[​IMG]
    <A target="_blank" HREF=http://www.off-road.com/chevy>http://www.off-road.com/chevy</A>
     
  4. talldogg

    talldogg 1/2 ton status

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    Shannon,
    There's been a couple of posts about converting from disiel to gas. Start there, I'd help ya with that, but I've never done it so I don't know what's involved. From there, there's very little difference between swapping a SBC with a BBC. First, the mounts, you'll definitely need new mounts. Make sure they're big block mounts as they're stronger, they have to handle more weight and torque. You have a couple options, solid steel mounts like ORD's, poly mounts like Energy Suspenion, and standard BBC mounts. It's up to you, how much you want to spend and how much "insurance" you want.
    You already have the disiel radiator, which is bigger than the 454 radiator, so you're covered there. Assuming you're getting the engine complete, from carb to pan, the last thing you need to consider is exhaust set-up. Whether you're going with headers or manifolds, you'll likely have to modify your current set-up or dump it all together, like me. Also, get the engine WITH the flywheel it has on there now, and you should be ready to go.

    It's not what you buy, it's what you build!
     
  5. talldogg

    talldogg 1/2 ton status

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    It sounds like the TH400 in the jeep has a Chevy bolthousing (unless it's a BOP pattern with an adaptor). The 454 has strictly been a Chevy bolt pattern block. If the 400 in the jeep is Chevy, then you need to double check on the bolt pattern for the disiel. If it's the standard Chevy bolt pattern, you're set. If the disiel bolt pattern is BOP, then you'll need an adaptor (Advanced Adaptors) or to swap the tranny.

    It's not what you buy, it's what you build!
     
  6. thatK30guy

    thatK30guy 1 ton status Premium Member

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    A friend of mine installed a th400 and np208 to his J**p J10 and kept the 360 AMC motor. I just cant remember if he had the tranny rebuilt with same or different housing. As for the diesel conversion, I would get or buy new gas tank or two if you have duals and before hooking them up, blow all the lines out that are running the sides of the frame rails. Make sure you spray some kind of cleaning stuff in the tubes first. My favorite is to use brake cleaner and then blow it out one side and then go to other side and repeat process.
     
  7. grumpy

    grumpy 1/2 ton status

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    What is BPO as it pertains to bolt pattern?
    David
     
  8. thatK30guy

    thatK30guy 1 ton status Premium Member

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    BPO is the code everybody calls "Buick, Pontiac, Olds". Their bellhousings are the same but different than GM. The top two bolts part of the housing dips down like a "U" instead of being "rainbow" shaped like the GM trannies.
     
  9. Donovan

    Donovan 1/2 ton status

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    Sorry I had to comment on this. The BOP case is like thatk30guy said. Also in the BOP case there is the Cadillac which is the same, so maybe we should call it BOPC. The only one of the GMs that has a different bellhousing is Chevy.


    Donovan
    <A target="_blank" HREF=http://www.rustbucket.coloradok5.com>http://www.rustbucket.coloradok5.com</A>
    Bigger is Better
     
  10. BigJohnson

    BigJohnson 1/2 ton status

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    My blazer had a 6.2 with a TH400 and I swapped in a new one when it went out and had no problems bolting it up. Also I swapped the engine to a 350 with no problems, bolted right up. One thing I will say, as someone has already mentioned, get a new gas tank. I had a lot of trouble with dirty fuel lines after my swap because I just flushed the tank with gas. If I had it to do over I would buy a new tank.
     
  11. JimmyDie6.2

    JimmyDie6.2 1/2 ton status

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    I actually did a diesel to gas swap, and left the tank, I had no problems, but I blew all the lines out with air. If you start with a clean tank and lines you should be fine.........js
     

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