1. dan brooks

    dan brooks Well-Known Member

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    I bought a 65 with a 273 engine in it, the engine is done, my question is can I put any 318,340 or 360 engine in it's place? I'd like to bolt replacement engine to current transmission. Thanks, Dan.
     
  2. Commando66

    Commando66 She's a beaut Clark!

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    What transmission? What year of transmission? Early 904's have a unique torque convertor snout. Early 4 speeds use a 9 1/2" clutch/flywheel/bellhousing that is not up to the task of a bigger engine.
     
  3. RustyRatRod

    RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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    Yes. There are a few small differences, but it;s a bolt in with the right parts.
     
  4. dart4forte

    dart4forte FABO Gold Member FABO Gold Member

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    You need a machined spacer to make the smaller torque converter snout work with the large crank register
     
  5. R3dplanet

    R3dplanet Well-Known Member

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    It isn't as easy as swapping engines. Instead you'll have a whole list of upgrades that you must suddenly tackle. I don't know much about automatics but I do know the process if you have a manual. Some of the following will certainly apply if you have an automatic, however.

    For one, you'll need another bell housing, clutch, shift fork, and maybe retainer bearing. The shift fork is longer with the 9.5" bell housing, so when you go to a 10.5" clutch and bell housing you need a short style later shift fork. So say to hello to much harder clutch pushing with your larger clutch and decreased mechanical advantage.

    Connected to that drive line is your small stock 7-1/4" rear end, which is too small for the added power. Now you need an 8-1/4" or 8-3/4" or maybe even a Dana or Ford rear end, which probably needs to be shortened (cut and welded) to fit your Barracuda .

    Obviously you'll need a new drive line, especially since you'll likely go with a newer more "standard" yoke-style drive line.

    Next, you'll likely need to upgrade or at the very least adjust your torsion bars. A larger engine like a 340 or 360 with larger bell housing will sag your front end. The Commando had bigger torsion bars for a reason.

    You'll probably need to rebuild your original radiator to a three core design and maybe add a clutch fan while you're in there to accommodate the higher engine temps.

    Of course, none of this matters if you're still stuck using the tiny/crappy/dangerous stock drum brakes. So you can bump them to larger drums or go with a disc brake setup. I have Scarebirds up front and 10" drums in the back (although I recently bought an SSBC rear disc kit for the back).

    If you go with larger brakes, and in my opinion you absolutely must, you need 14" rims or better.

    Oh, guess what? The best fitting exhaust manifolds for any small block are the stock 273 manifolds, which are adequate for the 273 but are quite restrictive for any other small block. Also, when fitting them you'll notice that the ports are offset even further by the later manifold port design on the heads - so now they're even more restrictive. So the manifolds will choke a later V8. You can try to find the '70-'72 Hi-Po manifolds, but they're expensive and really don't make a much greater opening and will absolutely NOT work with power steering. So now you're stuck with expensive headers that prevent anything else from fitting, are a bitch to install, and necessitate either a custom hydraulic clutch or re-welded Z-Bar that, if it fits, will barely fit at all.

    Last, you'll need a new mini-starter because that big old honking stock starter won't fit any more.

    So yes - technically you can bolt in another small block but be aware that it's very ignorant advice if someone claims that you can just pop in any old 360 small block and be on your way. If you do be prepared for the above mods otherwise your experience will range somewhere between inadequate to dangerous.

    I know all of this from direct experience on my own early As. When I first got into these cars many years ago a bunch of Mopar guys claimed up and down that you could throw a 360 in there and go for it. I listened to them and found them wrong. I have a 360 and you can too, but it's not as easy as a Saturday afternoon engine swap.

    Just to sound like the old man that I am, think about what the car is and what your goals are. I like to think of the Early As as less of a hotrod and more of a gentleman's cruiser. If you want to take it easy on yourself, hop up the 273 to Commando specs or go with a 318 which is basically a bored out 273. If your penis doesn't need the huge horsepower boost, then having your '65 with a 273 or 318 with reasonable power, reliability, and safety upgrades will keep you smiling wide more often. It all depends on the user. Some guys like to work on their cars all of the time, others like to drive them.

    Sorry for the length. I'm an old guy and just wanted to keep you from getting bad advice.

    -Red
     
    Last edited: Oct 2, 2016
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    • RedFish

      RedFish Well-Known Member

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      And since the lower radiator hose will very likely be on the wrong side for any later model engine you choose, just plan on buying a new radiator.
      I wouldn't trust my rebuilt OEM 273 to a 50 year old radiator either so spending money at radiator is included either way we go. Good luck
       
    • dan brooks

      dan brooks Well-Known Member

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      Thanks for the advice, I'm trying to keep it stock so the horsepower isn't an important thing. I definitely would like reliability with this one. To be able to drive wherever I wanted to go without problems. So then with that said, the 318 would be a much easier install than the other two? and what years should I be looking for??
       
    • RedFish

      RedFish Well-Known Member

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      Any LA 318 will be different at the crank register. That isn't such a big deal since someone stated there is a adapter bushing available. I think the water pump and lower hose rerouting changed at 1970.
      so 68,9 318 ?
      There wasn't a lack of reliability in the 65 273. If its rebuild able that's a reasonable plan.
      Me... I would want a good 67 273 simply because of that intake to head bolt difference found in a 65 273.
      No adapters needed. I can poke a variety of dual plane intakes on it ( cast iron 2 brl or aluminum 4 brl with just a little bit more cam ) quieter hydraulic lifters too, electronic ignition, and drive the wheels off it.
       
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      • R3dplanet

        R3dplanet Well-Known Member

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        Oh, right right right. I forgot about the water pump and outlets. Thanks for reminding us!

        Dan,
        The early 273 used a cast iron water pump. It's bolt-on compatible with the later and better aluminum water pump but the inlet and outlet ports are clocked differently, so you need a newer radiator and hoses. In my case I wanted to keep it stock looking and a local radiator shop was able to change the ports and add a core for less than a new radiator. It works great. Of course, your mileage may vary.


         
      • R3dplanet

        R3dplanet Well-Known Member

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        The 273 was perfectly reliable. Mine had 250,000 miles before it finally popped. When I went to rebuild it the pistons were not available at the time as they're made in batches and sometimes not available.

        The '64-'65 273 had slightly different threaded bolt patterns for the intake manifold. The '66 273 and then 318s and later used an intake manifold with different angles for the bolts. You can choose to either:

        a) Find an Edelbrock D4B intake manifold and call it a day
        b) Get a later LD4B and modify the mounting holes

        If you go with a 318, then the LD4B or Weiand intake would be a good choice.

        Look for a pair of casting #302 heads. The 273 is all about port velocity, not volume. The #302 heads are great and not too hard to find. They can be found here in the wand-ads or very often at Wildcat.

        Personally I like a hydraulic cam (less maintenance) and an Edelbrock 500cfm carb. The Eddies aren't the best performers, but they're easy to tune and hold it well. I always install a air/fuel ratio gauge so dialing in a carb is very easy. I'm a big fan of the Street Demon carbs but the smallest version (625cfm) is too big for the 273. Or hey, fuel infection. There's some cool threads on a good injection system over here: FiTech EFI system

        Any engine rebuilder can do a good job with a 273. At the end of the day it's just another LA small block.

        -Red

         
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        • RedFish

          RedFish Well-Known Member

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          Beware a conflict in late model heads ( like 302 castings ) and those early A cast iron manifolds. One member cracked his manifold and another did a tad too much grinding on the head.
           
        • toolmanmike

          toolmanmike FABO Staff Staff Member FABO Gold Member

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          Well said!
           
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