Putting 4 barrel on 318 2 barrel engine

1971 - 1974 Mopars

  1. Robert Schaad

    Robert Schaad Well-Known Member

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    Do not jump to putting an after market 4 barrel intake on your 318 2 barrel engine. Will bolt up and work but not as good as it should. The 318 heads have smaller intake ports and most 318/340/360 aftermarket intakes have bigger ports. This cause the intake air to be disrupted when going into the head. You can do a lot of grinding to port the heads to match the intake. Easy way is to find a stock 4 barrel intake that already matches up to the heads. I have a 318 in my 72 Satellite, that I found a 1981 Dodge Diplomat 4 barrel 318. Got the intake, and it matches up great. Put on a 390 CFM holley and runs great. Getting about 20-21 MPG on the road.

    engine 1.jpg
     
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    • Photon440

      Photon440 Well-Known Member

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      Finding your stock 4 barrel that matches up to the heads is great, but you must take into account that the 4bbl 318s that started in 1978 also had 360 heads and cam, which is why they shared part numbers for those components. That manifold may not have the same flow on an earlier 2bbl head 318. However, a 66-68 273 four barrel intake would match the 318 ports fairly well.
       
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      • WP29440SE

        WP29440SE Well-Known Member

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        the Eddy 2178 4 barrel intake or weiand 8007 with a 1406 is a vast improvement over the cast iron boat anchor egr factory intake. not to mention the weight savings. the mismatch between the ports is trivial. you'll forget all about it. that cast iron is the very first thing I ditch and have instant results.
         
      • moparmarks

        moparmarks Well-Known Member

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        This works great on the 318.

        20190923_171703.jpg 20190923_171715.jpg
         
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        • rumblefish360

          rumblefish360 Well-Known Member

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          Photon440, could you clarify this please.

          I agree with this except;

          1) The OE 4bbl. is actually a good intake manifold that should be able to be had on the cheap. Blocking off the EGR valve, IF it isn’t on the i take already is a simple home cobbled steel plate and correct high temp gasket. Inside the intake, of the 2 floor jets, 1 can be screwed out and a Allen head flat plug can be installed. The other floor jet may or may not be the same. If the floor jet is a simple cast in hole, a quality epoxy can be used to plug it up. Now the intake is as good as the earlier70’s units.

          2) The Edelbrock Performer doesn’t perform any better than the OE intake. I do not know about the Stealth.
          But I will say on such a low powered 318, the difference would be small.

          3) I have a Weiand Stealth (8007 I think it is)
          (1) I wasn’t too fond of the casting on several fronts.
          No coil mount on the intake. I fab’ed up my own 6 pack like bracket and used an epoxy coil. (See below)
          (2) I had to grind away on the outside runners to get the bolts next to the runners in. This could be due to them being ARP hardware, longer bolts than stock? IDK for sure.
          3) Core shift was on the rough side.

          4) The weight savings of about 25lbs. is the only advantage I can see. If 100lbs. Is a tenth gain in the 1/4 mile, then what is the actual gain on 25lbs.?


          That intake was specifically designed as a mileage intake manifold. Designed, cast and sold during the gas crunch era. It was also available in a 2bbl. version.
          Another intake on that level of the idea of more mileage is the Edelbrock Streetmaster.

          Below is the sp2-p (318 2V) by Edelbrock in the 2bbl. version.
          695327C7-90F4-4831-B249-01D108F5307A.jpeg 4BC783C7-6C40-4846-BD4F-F498BEA30A17.jpeg

          The Weiand Stealth below. Note coil position.
          45F397B6-1C75-47AB-BE3D-BA1AC89F1F7B.jpeg 3CE016D6-9CA3-4692-8B9E-F40AA6327186.jpeg 12342906-DB14-47F9-A8A5-D73337DB89E1.jpeg 36E5115E-61BD-40E5-84E2-364EF70E856F.jpeg 4F2BFCB4-585C-4AD7-A45E-0B27606B0F9E.jpeg
           
        • rumblefish360

          rumblefish360 Well-Known Member

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          Nice job. I personally would have used a 600 cfm carb. I’ve done this with an Edelbrock LB4, *I Think* it was. I’ll have to check that.... but any ways...

          What ignition do you have?
          Headers?
          Single or dual exhaust?
          Pipe size?
          Gear ratio and tire size?

          IMO, I think you can get a little more mileage out of this engine.
           
        • 66 Sat

          66 Sat Well-Known Member

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          Well I had GREAT results with an Edlebrock Performer/600 Holley and headers on a '69 Barracuda 318. The weight savings are not all about straight line speed anyway. That weight is way up high in the engine bay, so by reducing it you're improving your centre of gravity, so better cornering. Also, it's easier to stop with less weight. Simple physics. More power and torque, less weight. What's not to like?
           
        • Robert Schaad

          Robert Schaad Well-Known Member

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          Agree. I had other sets up on my 318, 650 Edlebrock with aluminum intake. Great performance, more power, better sound. But I wanted more miles per gallon. So I changed and got more MPG. It depends on what an owner wants.
           
        • Robert Schaad

          Robert Schaad Well-Known Member

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          Every 360 head I have ever seen had the bigger intake ports. The 81 Diplomat that I took the stock 4 barrel intake off of had the smaller ports. The intake was never changed because the Diplomat was a county car from new. That is the main reason I purchased it because I knew it the ports were the same.
           
        • Robert Schaad

          Robert Schaad Well-Known Member

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          I used the 390 CFM Holley because I wanted the 4 barrel look but the 2 barrel MPG. Took off points, put on Mopar electronic conversion, duals off stock exhaust manifolds, 2 1/4 pipes, 2:71 rear gears in 8 1/4 rear. Sounds and looks great. Don't get me wrong, I had other set ups on the car, 650 Edelbrock and aluminum intake. It actually had more power, and louder, but got less MPG. I am going back to as close to stock look as I can. Pulling mopar valve covers and air cleaner and replacing with stock ones and dual snorkel air cleaner.
           
        • toolmanmike

          toolmanmike Moderator Staff Member FBBO Gold Member

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          Probably the best performance small port 318 manifolds are the Edelbrock LD4B and the Weiand (#8022 I believe) A 600 Edelbrock is a good choice for a stock cammed Teen.
           
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          • Robert Schaad

            Robert Schaad Well-Known Member

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            I think sometimes we do not take in consideration of the Fuel available today. So much different then the good old days. My set up allows me to use cheep gas at all times. No ping, good performance.
             
          • rumblefish360

            rumblefish360 Well-Known Member

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            LOL! I like how you kind of dismiss the straight line drag performance parameter but play up the better handling and breaking aspect.

            The 25lbs. weight difference is not going to be felt in ether case. But I do agree it is a step in the right direction.

            I have also done 318 hop ups. The last one I did, I mentioned above with the LD4B intake. The 318 was further equipped with at onetime a Holley 600-1850 & then a Federal Mougal 600 AFB. Hooker headers, Jegs exhaust (2-1/2) and a small Crane Hyd. 216/228-./454-.480/112. It was in a Duster, 904 & a 3.21 suregrip equipped 8-1/4.

            It was fun! It spun the stock sized tires way to much at the track.

            But as Robert said below.....

            Indeed it is what the owner wants. My motto, “Your car your way!” Though I never did a 318 for mileage. I did do a ‘79 Dodge Magnum for one. No headers and it needed cats. I did a dual exhaust with dual cats. In the end, i managed 20 MPG’s on crappy 87 octane.
             
            Last edited: Jan 7, 2020
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            • toolmanmike

              toolmanmike Moderator Staff Member FBBO Gold Member

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              You bet Rumble. Those Teens are pretty versatile. Good mileage or good performance or a little in between if you want. LOL
               
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              • rumblefish360

                rumblefish360 Well-Known Member

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                I had a bit of fun with my on the cheap project on FABO.
                It was a shame I had to get rid of the car without getting to the goal and to make the point.
                 
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                • Photon440

                  Photon440 Well-Known Member

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                  Head casting numbers for a 1981 318 4bbl should be 4071051 which is a 1.88/1.60 valve engine. It is the same as the 360 for that year. A 1981 318 2bbl would have smaller valve and port heads #4100405. I'm not disputing that every 360 head you've seen had bigger intake ports, I'm just saying that the same heads were also used on 318 4bbl engines but not the 2 bbl versions. I haven't found a casting number list that shows a small valve head on a 4bbl 318.
                   
                • 66 Sat

                  66 Sat Well-Known Member

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                  I could definitely feel the difference driving on twisting country roads in the UK. Maybe you wouldn't notice so much in stoplight to stoplight driving in the US though. I've also felt a difference going the other way with my Satellite - changing from a Weiand 7503 aluminium intake to a factory 4 barrel cast iron manifold. Going around roundabouts the car definitely tips in more. If the weight was down low in the chassis, like frame connectors, it would be less significant. When you lower a car by only 1 inch it makes a difference, or increase tire width by 10mm. Only small changes but they can be significant. Everyone's "seat of the pants" feeling is different. The way I drive my cars I'm very sensitive to the set up. When I took my car apart and then put it back together again I was amazed at the weight of some items and the ease that weight could be saved if they'd been manufactured with that in mind. The "Satellite" badge between the rear seats must weigh about 2 pounds, there's a thick steel plate that joins the centre console and the fake vent at the back of the console that probably weighs the same. I wouldn't want to lose the solid feeling of the car but I often think if I won the lotto I could get all the easily removable body panels made in aluminium (fenders, hood, doors and trunklid), put in some lightweight framed seats, suspension components, wheels etc and save 30% of the car's weight. The poly would have to go though....
                   
                • rumblefish360

                  rumblefish360 Well-Known Member

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                  LMAO!

                  Your telling me you can feel the difference of 25lbs. in the car and where?

                  You so full of it.
                   
                • 66 Sat

                  66 Sat Well-Known Member

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                  Ok champ. We're all identical and I'm lying to look like some sort of weight-sensing hero on the internet. Don't know why I bother sometimes. Over and out.
                   
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