273 Numbers Matching car. Should I rebuild or swap engine?

Small Block Mopar Engine

  1. Tadams

    Tadams Tadams

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    Welcome, there are definitely a lot of opinions here. I have a 273 commando and plan on keeping it original. I'm not planning on selling the car. Hoping to have the paint complete soon. I just wanted a different car to cruise around, not to race.
     
  2. JT-68-Dart-GT

    JT-68-Dart-GT Member

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    This may be a stupid question, but I think there are different "versions" of motors in say a car, versus a truck, versus an RV for example like in the Large Blocks. I assume the small blocks are the same deal??? Let's say I want to go with a 318 or 360. I had a guy locale tell me if I went with a 318, "everything" on the 273 would bolt right up - simple drop in - from the transmission to the Air Conditioner, etc... But on a 360 I can't recall what all he said was different but it would not just drop in. Other things would be needed to make it work. So if a 318 is a "Simple" drop in where everything bolts right up, then to me that seems the way to go to get some extra torque - but would it be enough to tell over a larger Cam in the 273 like some have mentioned? So is it true that the 318 is a "Drop in" and if so, if I want to locate a used engine, what years will work in our '68 Dart? And what "car" or "trucks" would be the years and models to look for that would be less expensive. Example, an Early CUDA might have a 318, however finding an old Scamp or Demon - or maybe an old Pickup (not sure make or model) would be cheaper than the CUDA! So as I search around here locale, any idea on a shopping list of car and truck makes and models to watch for as well as the year range like a 1966-1980 or something? I appreciate the input. Oh... and if the 360 is "a lot better torque" by a great deal than the 318 - then the same questions on the makes and years (cars v/s trucks) to look for around town that would have that motor and the best bang for the buck... or would you just go drop $4000 for a Blue Print Crate engine and be done with it? Again, my wife just wants a 'nice dependable car' she can cruise around town in and show off her DART. Seems like a Crate with a warranty v/s some old motor I have to rebuild is about the same money... so hit me with your opinion on why more people don't just buy a crate? I've had a lot of cars - but they were all ready to go... this restoring and rebuilding old Mopars is all new to me... I was about to lean toward a 360 Blue Print Crate, but if the torgue is not that much different them maybe a 318 BLue Print Crate is the way to go if it's a drop in and if the majority here says it's a good idea to head that direction.. At least that is the way i was headed until I found this website and Forum - which all of you guys are amazing... you all have genuine knowledge on these Mopars - most of the Gear Heads in town spin more BS than knowledge. Thanks in advance for steering me in a direction. And let me say that I am not a stickler on a nut and bolt restoration and keeping it all 100% original. I am more interested in giving my wife a fun little car "that is dependable" and I do not have to worry every time she takes our kids down the road for a spin and I am not in the car should something go wrong and it "die". So with all of this in mind - anyone and everyone please 'Chime In' on the bat way to make this happen... and I am not afraid of an older motor with a good rebuild - I have a super mechanic here. I just want more than 1 opinion to weigh out. Thanks!
     
  3. JT-68-Dart-GT

    JT-68-Dart-GT Member

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    Congrats on finding a 340... I looked around for one for the dart but they are hard to find. My '70 CUDA was a 340 car, but the guy I bought it from replaced it with a 440 4 barrel (and sold the original 340). I just upped it to the Six Pack with an original '70 intake and new repro Holley Carbs and it's running like a beast. I wish that he had kept the 340 and that it had come with the CUDA which would have solved my problem. I would have tossed it in the Dart and put the 273 in Storage. :)
     
  4. toolmanmike

    toolmanmike Moderator Staff Member FABO Gold Member

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    Some good info there!

    May be too much for the OP's wife to enjoy. LOL
     
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    • Sedanman

      Sedanman 67-9 Valiant specialist

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      I got really lucky on CL and it was complete carb to pan with all acc's for $350. The 360's are much easier to find and just as good. I will have to relearn how to drive it with this much power once I get all of the bugs worked out. It barely got out of it's own way before the resto and the only way it would spin the tires was in the rain lol.
       
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      • nm9stheham

        nm9stheham Well-Known Member

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        Since the OP has a '68 273 then the 318 should drop in unless the '68 273 is a very early '68' and has a small crank register hole perchance. The one thing to be aware of is that the hole in the back of the crankshaft where the torque converter snout fits in (crank register), is larger in the '68's and later.

        Yes, there are different 318 pistons out there (truck vs car) but they are all low compression engines; the trucks are just lower. This makes them 'soft' in the lower RPM's ranges; i.e.; not much low end torque. It is very desirable from a performance standpoint to correct this issue for the 318's, so a custom build speaks more to that. The same really applies to 360's. The later Magnu versions of these engines fixed that low CR issue to some degree, so IMHO are more desirable from a performance standpoint.

        For the wife, I think I'd think 318. You have a light car to start with, and something that takes a lot of throttle management may not make here happy.... but you know here likes and dislikes better than us. I have an acquaintance who went from a '68 273 to a 400+ CI stroker, and he says it ruined the car as a family 'go to the drive-in on Saturday night' easy driver car.

        The car 'dieing' randomly is a much different matter than the engine....look at the electrical stuff and brakes first.
         
      • JT-68-Dart-GT

        JT-68-Dart-GT Member

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        Well... in the last 12 hours since my 1st post I have learned a great deal - thank guys - all of you:
        1) I have learned about all of the above and options.
        2) I have learned that when you have a conversation with your wife 3 weeks ago and finally get time to move on the project - take time to recap.
        3) We just returned from lunch - I gave her a run down of what you guys have told me, we talk Torque and Horsepower - she has been with me in the CUDA - not really Hot Rodding, but bumping the throttle on occasion and popping her neck back (lol) - so she gets it... So after a lengthy conversation on options she say, "I want my 273 rebuilt. I don't want to go fast, I want to go slow and cruise. I'm cute and want everyone to see me. If I want to be a blur, I will ride with you in your CUDA". And as a good husband does, I asked her permission to quote her verbatim and got it. That's the funniest line I have ever heard! lol. So I give up. I tried to get her to go with a bigger engine but if she want to "go slow" - as well as the fact that she has some nostalgic connection to 'keeping the original motor' for some reason... then I guess I will fork out the extra Cash to build the Little Engine Than Could (break me). So, I will search the Forums for a Parts List, to rebuild kit, and all the things I will need (unless someone has a neat down and dirty grocery list with companies to buy the parts from) that would be Awesome as she is wearing me out - now I just want to get it built! I will at the least make it where she can burn any type of gas (Ethanol) so I will need those special parts to do that. Thank you guys again for taking the time out of your day to give me some ideas... Here's to rebuilding a 273.
         
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        • yellow rose

          yellow rose Overnight Sensation

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          Listen to what I say, but I'm thinking you know this. If I'm preaching to the choir I apologize.





          HAPPY WIFE=HAPPY LIFE.

          Give her what she wants.
           
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          • seabee

            seabee FABO Gold Member FABO Gold Member

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            Personally, I would compare some options between a 273 rebuild and what you can find in a complete 318/360 "cruising" motor and putting the 273 on a stand for later.

            That is what I did.
             
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            • 273

              273 Well-Known Member

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              Could always make a 300 or 336 out of the 273 with a 3.58" or 4" stroke lol

              Since your stuck with the 273 I'd just use the stock flat top pistons you can get and zero deck add 318's 302 heads and a .040" gasket with a 500 cfm performer carb and intake and a 250 ish cam and duals and call it a day.
               
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              • nm9stheham

                nm9stheham Well-Known Member

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                With the lower compression 2 BBL Egge L2221 pistons you would have to deck the block .040" to get them to zero deck, and then you would still only have 8.4:1 static CR with .027" thick Cometic gaskets (assuming they make 273 gaksets from that thin MLS material) and 302 heads. IMHO shave 302 those heads another .040" to get to around a58 cc chamber..... then you are a 9:1. But it sure would be easier to use the Egge L2222's and not bother to deck the block.

                The OP has a '68 2 BBL 273 and that would have the 675 heads IIRC, with around 68 cc chambers. So smaller chambered heads sure do make sense.

                OP, you have about the clearest marching orders you could ever get! They make complete sense to me LOL

                BTW, OP, what do you mean about burning ethanol? Do you just mean burn standard gas with up to 10% ethanol?
                 
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                • toolmanmike

                  toolmanmike Moderator Staff Member FABO Gold Member

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                  I always wanted to see how a zero deck flat top 273 with small chambered heads would work..
                   
                • ir3333

                  ir3333 Well-Known Member

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                  i know i'm late to this party but you can't go wrong with a 340 Dart.
                  It wins in every category and has everything going for it!
                   
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                  • JT-68-Dart-GT

                    JT-68-Dart-GT Member

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                    Yes... I just meant gas with ethanol v/s100% Gas.
                     
                  • nm9stheham

                    nm9stheham Well-Known Member

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                    OK, just a word to the wise..... don't leave that fuel in your tnak and engine without fuel treatment like Sta-bil. Even 3 months sitting with 10% Ethanol can mean a gummed up carb, and gum in the bottom of the tank.
                     
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