318 REBUILD IN 67 BARRACUDA

Small Block Mopar Engine

  1. 67BARRICONVERT

    67BARRICONVERT Well-Known Member

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    The trans #s are 2801536y and 2517732. I believe its the original trans. Thanks for the manifold tips, I will check it out.
    trans #s 1.JPG trans #s 2.JPG trans top.JPG
     
  2. 67BARRICONVERT

    67BARRICONVERT Well-Known Member

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    Thanks Furrystump, thats mighty kind of you! Since I already have my exhaust I think for now I will go in the direction I am going. Like you said now would be the time and it would look so much cooler but for now it will stay original,
     
  3. 66fs

    66fs FABO Gold Member FABO Gold Member

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    Part #2801536 from a 1967 "A" Body 273, 4 barrel carb. Close enough, sounds original to me.
     
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    • cudamark

      cudamark FABO Gold Member FABO Gold Member

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      ^^^^^yup, sounds like it. Just check your 318 crank to see if it has the reducer bushing in it. If not, get one to help center the converter.
       
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      • 67BARRICONVERT

        67BARRICONVERT Well-Known Member

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        Will do Mark, I am going to go by the machine shop to check because if there is one in it I dont want them to loose it and then tell me there was never one in it.
         
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        • furrystump

          furrystump Well-Known Member

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          Really, never knew that. Thanks, learn something bew everyday.
           
        • Mopar44134

          Mopar44134 Well-Known Member

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          Im a little late to the party....here's my 2 cents. Eventually i would like to go back to a cruiser/driver, reinstalling the AC. I dont think i would go back to iron exhaust manifolds, hp's maybe but Id look at making the 318 more efficient. Clean up the heads, smaller valves helps the low end, off idle, fuel atomization. If you stay with a milder cam, 2.02's overkill. 9.5 compression is my target. Possibly going to an LA roller 318 or magnum with LA valve covers. I too like the stock look.

          904 Transmission, lighter internals, less power loss. I thought about an overdrive....lighter a500, so i could stay with 3.91's. I like the off the line, 1 - 2 shift with a good chirp to surprise the unsuspecting. i was following a /6 fastback years ago, i had a cammed 318 with 3.23s. He jumped me off the line, caught him by 2nd and pulled away. He had 4.10s 8.75.

          my 7.25 with 2.76 lasted, i swapped to an 8.75 but for a cruiser i thought about finding a lighter 8.25. My thinking for the whole project, lighten up the entire rotating assembly to free up power and minimize power loss. Squeeze out fuel mileage for when gas is hard to come by.

          Nice car and build!
           
        • AJ/FormS

          AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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          You don't need big valves in a 318 streeter, for one thing.
          And to make best use of premium fuel, you will need a final cranking cylinder pressure of around 160 psi, but to stay out of detonation with iron heads, no more than ~165psi.

          The thing with alloy heads is, that you can run the pressure up to, in the range of 185 to 200psi. I run 180psi on 87E10.
          Pressure is power, specifically at low-rpm. Which is what a longer-period cam always gives up.
          Plus, when the bug for more power bites, the alloys will bolt right on to the biggest of small blocks; and you won't be stuck with the useless open chamber big-valve heads that you spent good money on.

          IMO, with a 318streeter, you can sacrifice whatever you want to, so long as it ain't pressure.
          Without the pressure, and WITH a bigger than stock cam; you will need a higher than stock stall and quite a bit more than 2.76 gears. I'll guess a 2800 and 3.23s at a minimum, up to 3.91s preferred..
          The point is this; that altho the buy-in for the bigger cam is relatively small, the loss of pressure will end up costing more money.
          But the even-bigger picture is that NONE of this makes any sense at all, breathing thru 273 logs and a single exhaust. If your engine has to pump it's own exhaust out, that costs power. And gas money

          BTW-1
          The Second generation Barracuda is the heaviest of the A-bodies of it's era. And that, on a 108" wheelbase, go figure. The folding rear seat is a tank, and the buckets/console is more fat. The heavy back glass is at least in the right spot.
          To it's advantage are the very roomy rear wheel-wells. With a little work I installed 325/50-15s into mine; on alloy wheels of course cuz they weigh about half of the same-sized steel wheels.
          Happy Hot-Rodding
           
          Last edited: Sep 18, 2021
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          • 67BARRICONVERT

            67BARRICONVERT Well-Known Member

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            Thanks for the /6 story....good times! I kind have my heart set on keeping it looking stock looking down to the 273 commando valve covers, and the A/C is going back on the car. I agree with the 2.02s being overkill, but I am thinking 360 size valves. I also agree with your 9.5 compression mark. Thanks for the input!
             
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            • 67BARRICONVERT

              67BARRICONVERT Well-Known Member

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              Thanks AJ, I agree with the puny manifolds, but at least it wouldnt be too hard down the road to put on headers and a real exhaust if I change my mind. It is interesting how heavy they were. Although mine does not have a folding rear seat or the huge rear glass.....Its a convertible:lol:
               
            • 66fs

              66fs FABO Gold Member FABO Gold Member

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              If you bothered read, he is building a nice driver for his wife, AC and all. A 1967 Barracuda convertible with a Commando drive train. He already has a new Commando exhaust from Accurate. I doubt you loose much hp from the 273 manifolds and exhaust. I ran that exhaust for years and later switched to duals, to gain nothing. Mine was the 65 Commando set up with a 2.5 inlet, straight thru muffler. Should be a blast to drive, and get great gas mileage. Not everyone is a boy racer.
               
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              • AJ/FormS

                AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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                OP; you say;
                and this is to be for your wife? ............... Gimmee a break.
                I know what it takes to get a 318 up to 9.5 or more, and I know that a 260* cam is no small thing. And I have heard more than a few people complain about California gas. And, depending on your elevation there in SoCal, the cranking cylinder pressure could be over 160psi@ 9.5 Scr, which sorta demands Premium fuel.
                IMO, this shaping up to be a recipe for disaster.

                Furthermore; the worst part, IMO, is to saddle this log-exhaust engine with 3.23s in the which, the fat part of the torque curve in First gear doesn't arrive until say 30mph, and the powerpeak at say 50mph; and, the top of Second gear will not come until over 85 mph. What's the point of all those engine mods if you never get to where the power is......
                IMO, you might as well just keep the long-block stockish (with a slight bump in Scr), and run cheap gas..
                IMO, I would let the target pressure dictate the build. I would shoot for something like 150/155psi for California gas, at your local elevation;
                which could be; 9.2 with that 260*cam, or 9.0 with the next smaller cam.
                The latter of which is likely to have a stronger bottom end.
                Which is, IMO, what the wifey's ~3500 pound loaded convertible cruiser needs, to pull those 3.23s around town, with a typical stall convertor.
                ==================
                My 68 fastback with a 367/manual trans/8.75/no A/C / but With power steering and brakes,
                weighs in at 3450, me Not in it. I lightened it quite a bit with an alloy-cased 4-speed/alloy top-end / alloy wheels/ no rear seat/no console/and lightweight buckets.
                ==================
                If I was gonna build, (which I never will) a 318/ Second gen Barracuda stuck with 3.23s;
                it would have a tight-LSA Solid-lifter modest-period cam (like the 260), and a Commando 4-speed. But if I have to give up the Commando, then it would have the (wide-ratio) 2.74/1.54/1.00 automatic, a slightly wider LSA cam, with at least a 2800convertor. And no matter what cam is in it, I would want to run headers or at least 340-sized logs; even if I was forced to use the stock hydro cam, which really ain't all that bad for a cruiser application.
                But if I could run more rear gear, then I would run the Regular (close-ratio) A904 gear ratios, with a lower stall, and a slightly tighter LSA.
                For Performance; this combo wants a starter gear of between 10:1, and 9:1. With your A904 and 3.23s the starter is a mere 7.91, leaving you about 20% short of performance on take off. Your cylinder-pressure and stall will have to make up for that deficiency.

                But if it really was a convertible cruiser destined for my wife,
                I would forget all about such things.
                Instead; I would get her a Bug, or a Rabbit, or a Fiat500, or a Smart-Car even; cuz wives tend to drive a LOT!, especially the stay-at-home kind....... which, tooling around on Premium, won't be cheap, and will only get more expensive in the future.

                What I want to know is this;
                why OP, why would you think of building a hi-compression, big-valve, 4bbl 318, with a big enough cam to worry about how much vacuum it pulls ....... for the Mrs to cruise around in; ....... and then stick it into one of the heaviest of the A's, and finally, choke it with 273 log manifolds and 3.23 gears? IMO, this is messed up.

                Does your wife really care about such things? Will she ever even floor it? And if she does; will she hold it there long enough for the secondaries to start working, or to find the power in Second gear, which with 3.23s, doesn't even arrive until well after 60 mph, nor finish until perhaps 80/85 mph?
                If the answer contains just one no, then what is the point? IMO, you are very likely leaving out a part of your story, possibly the part about you wanting to go ripping around on weekends ...........

                Please notice that throughout this post I never once said a single word about starting with a bigger-bore/longer-stroke engine, which would of course, solve all your problems as I perceive them; including the stall/3.23 thing .

                As always;
                Happy HotRodding
                 
              • 67BARRICONVERT

                67BARRICONVERT Well-Known Member

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                Thanks Aj. Yes, this is the wifes car. We attend car shows with my cars and the wife wanted a car of her own so she dosnt have to ride shotgun, so this car is for her. Will I drive it? Hell yes! I am asking these questions on here because of the points you just brought up. I do not want to hurt performance, I just want to wake it up a little. The original compression ratio of this engine is pathetic so the goal is to just take it a step up. I have lived in Cal. all my life so trust me, I have been dealing with the fuel here. I have pre 1970 cars that came from the factory with 11:1 so I get it.
                 
              • Richard Sweet

                Richard Sweet Well-Known Member

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                I don't believe that anyone would want to remove the exhaust manifold butterfly valve if they were going to keep single exhaust. That valve is supposed to reduce backpressure from the other side, so it needs to be kept loose and able to move freely.
                You should also consider what type of choke you are going to use, e.g. the one that needs the exhaust heat applied to the intake manifold choke spring or electric or manual. Maybe the LD4B intake manifold doesn't have the heat pot in it, I don't know.
                If you are going to use electric or manual, you really don't need the intake manifold to be heated unless you live in a cold climate. An electric choke would be another thing you could use if you changed to dual exhaust.
                Also consider if you want the heat crossover port in the intake manifold to be heated or not. There are intake manifold gaskets that block off that crossover port.
                Richard
                 
                Last edited: Sep 19, 2021
              • 67BARRICONVERT

                67BARRICONVERT Well-Known Member

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                Thanks Richard, I have been meaning to ask that question about the heat crossover port. Both carburetors I have are electric chokes and I was wondering if there was a way to block off that port. I will check the gasket set I have. The manifold butterfly works freely, in fact I was surprised how well it worked. Usually I find them froze.
                 
              • Slantsix64

                Slantsix64 Well-Known Member

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                • 67BARRICONVERT

                  67BARRICONVERT Well-Known Member

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                • 67BARRICONVERT

                  67BARRICONVERT Well-Known Member

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                  This is the distributor that was in the car. #3690430
                  distributor.JPG
                   
                • 66fs

                  66fs FABO Gold Member FABO Gold Member

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                  That is a good one. Mopar Performance HP, vacuum advance, electronic distributor. About the same as the 72-73 340 distributor.
                   
                • 66fs

                  66fs FABO Gold Member FABO Gold Member

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                  I always delete the exhaust butterfly. Have you seen an aluminum intake after that valve has frozen up closed? Headers and later engines as well as Magnums do not use a butterfly. As far as I know it is to heat the intake faster to pull the choke off. As for single exhaust, the Commando single exhaust is very nonrestrictive.
                   
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                  • 67BARRICONVERT

                    67BARRICONVERT Well-Known Member

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                    This is the coil bracket that was on the car when I took it apart. Does anyone know if it looks correct? It was mounted only using one of the two bolt holes. Its the LDB4 intake so maybe it takes a different bracket?
                    coil and bracket.JPG
                     
                  • RustyRatRod

                    RustyRatRod I was born on a Monday. Not last Monday. FABO Gold Member

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                    Since it sounds like it needs boring, choose a flat top piston with four eyebrows with the tallest compression height you can find. Those pistons in it now have a dish and four eyebrows. Low compression. Since you don't have the original engine, let's not be picky and try to keep it original. If it was me, I'd put some 302 castings on it, or 5.2 Magnum heads. Some people scoff at the 302 castings, but as mild as it sounds like you're going, they'll be a nice addition and, unlike the Magnum heads, the LD4B intake will bolt right up to them. With the pistons I recommended, I suspect you could get compression close to, if not a hair over 9:1 and that's just perfect for what you want.
                     
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                    • Brooks James

                      Brooks James Dustoff

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                      Very nice, there is a thread here somewhere on an a500 Install, read it before you commit
                       
                    • 67BARRICONVERT

                      67BARRICONVERT Well-Known Member

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                      Thanks Rusty, thats kinda what I was thinking on compression or maybe a tad higher.
                       
                    • 67BARRICONVERT

                      67BARRICONVERT Well-Known Member

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                      There is no reducer in the crank. Looks like the crank is about 1/4 inch larger than the torque converter hub.
                       
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