What mileage does your slant six powered ride get?

Slant 6 Engines

  1. Garys72Duster

    Garys72Duster Well-Known Member

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    That' prob the best way to do it. For example, I filled my car up, drove 176 miles, filled it again. Took 5.9 gallons to fill it back to the top of the tank. So I take 176 miles, divided by 5.9=29.8 MPG. Then you can keep a running log, each time you fill it, then average all readings.
     
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    • a12

      a12 Well-Known Member

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      Pinocchio2.jpg
       
    • moparblood

      moparblood Well-Known Member

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      you can call it whatever you want. it still is what it is. its Not that hard to believe. why bs about it? as i stated NOT all motors are the same!
       
    • Garys72Duster

      Garys72Duster Well-Known Member

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      I got 11 MPG with my 70 Dart, 440, driving from LA to Denver. All Hwy. NO KIDDING! Found out the primary power valve on my 750 Holley was blown, and always open.
      I was wondering why I had a trail of black smoke coming out the back. True story.
       
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      • doc540

        doc540 Well-Known Member

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        Are you a wagering man?

        doc holiday2.jpg
         
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        • Slantsix64

          Slantsix64 Well-Known Member

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        • Ddaddy

          Ddaddy I'm changing the World... one pixel at a time! FABO Gold Member

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          That sounds about right. I’ve owned and regularly driven probably a dozen slant 6 cars in my life and never saw much better than around 18 mpg on the highway. Of course, none of those had an OD transmission.

          If I could average 17 mpg in mixed driving, I thought it was good enough since I always tuned for power...not mpg.
           
        • RustyRatRod

          RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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          That is exactly right. The more fill ups in your average, the more accurate your average. Also, you need about a "half and half" mix of city and highway driving to be even more accurate.
           
        • 318willrun

          318willrun Utube channel 318willrun

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          I like to at least go over 200 miles on the tank, but the more the merrier. If I can fill up at the same pump, that's even better. A 3 tank average is even better. Gas mileage is rated city/highway. Also, lots of hills play a part. This being said.....
          • I had a '74 Dodge truck, slant six 1 bbl 4 speed. 24 mpg going back and forth to work at 55 mph. Yes, the odometer was accurate. I commuted 34 miles one way.
          • My dad had a '68 valiant with a slant that got 28 mpg on the interstate. Like it or not, believe it or not, it's what it got. He drove from Colo to Wheatland, Wyoming to work. We also took it from Colo to Washington.
          • We've had some that stunk at gas mileage too, because something was wrong with them.
           
        • doc540

          doc540 Well-Known Member

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          Just made the gear change along with a new intake/header gasket.

          A tad lean, but the mileage run was purposed for an accurate check.

          Filled up at the same pump leaving and on return.

          1961 Lancer
          A904
          2.73 rear
          Pertronix ignition
          Head work, mild cam, Clifford intake and shorty headers, Holley 390
          91 VP non-ethanol

          24mpg highway at 65mph

          lancer plug13.jpg

          lancer air cleaner decal1.jpg
           
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          • Princess Valiant

            Princess Valiant Duster specialist FABO Gold Member

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            The OD isn't really what people think it is. The last gear is not a very responsive gear to the throttle so you end up down shifting a lot. Even on the interstate I find the last gear isn't enough to pass someone. I am always down shifting for more power so it defeats the point of the OD and ends up being more like a standard three speed.

            I suppose the OD works better if you kept at a constant 55 but trying to keep it between 78 and 88 mph in a 75 zone requires a lot of downshifting to 1:1 just to keep up with traffic.
             
          • Princess Valiant

            Princess Valiant Duster specialist FABO Gold Member

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            Where did you get the air cleaner decal, that's badass
             
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            • Garys72Duster

              Garys72Duster Well-Known Member

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              And is that engine paint Chryslers Corporate Blue, used on early 70s motors? Very nice looking motor!
               
            • doc540

              doc540 Well-Known Member

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              Thanks

              Daughter had the decal made for Father's Day gift. (she's a graphic designer, but just modified a decal I found on the net)

              Engine color is "kind of" a Petty blue that a local powder coat company had in stock. They said other MoPar owners had used it on their engines.

              Interior is blue and black, so...

              lancer interior2.jpg
               
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              • 66fs

                66fs FABO Gold Member FABO Gold Member

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                • moparblood

                  moparblood Well-Known Member

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                  the OD gear is more like a 5 speed with No 4th. when doing these averages, its at 55mph should be No or No less. when you increase the HP on a motor, you most likely substitute mpg's. or go over 55 mph.
                   
                • toolmanmike

                  toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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                  Or make your own. 100_5189.JPG
                   
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                  • a12

                    a12 Well-Known Member

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                    up to 24 is believable, but after that

                    th (1).jpg
                     
                  • RustyRatRod

                    RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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                    I wonder what difference a T5 transmission might make? Food for thought.
                     
                  • RustyRatRod

                    RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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                    I agree with the others. That does look real nice.
                     
                  • 66fs

                    66fs FABO Gold Member FABO Gold Member

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                    No O/D not mine, documented from 1964. If you read the article, it describes conditions, and that these were off the lot cars with strict fueling and non tampering policy. LOL that you guys can't believe some of the stuff that some of our members have achieved. Mine by efficiency as I was building for power, not fuel economy.
                     
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                    • Charrlie_S

                      Charrlie_S Well-Known Member

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                      I was building for fuel economy, and my engine is not stock. So I don't understand why some don't believe that I can get upper 20's MPG
                       
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                      • Slantsix64

                        Slantsix64 Well-Known Member

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                        What set up are you running in that 390? wheres your timing at. Also that is a badass air cleaner decal
                         
                      • doc540

                        doc540 Well-Known Member

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                        Thanks

                        I'll have to ask my old friend and mechanic what jets we ended up with.
                        And we just set the timing by ear and feel.

                        Got it running like a Singer right now.
                         
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                        • KosmicKuda

                          KosmicKuda FABO Gold Member FABO Gold Member

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                          That's what I'm talking about! Chrysler cars always kicked ass in the Mobil economy runs.

                          Of course, if you know anything about Chrysler engineers you KNOW they studied, tested, and honed their techniques. Give them a challenge and they came out in top. From what I remember they accelerated to the speed limit quickly but not enough to waste gas. IIRC, there was an official observer in the cars to check for cheating.

                          But at least one time they put a ball bearing in the ash tray and used it as an inclinometer.
                          Our old cars had, and still have, an advantage due to those anal-retentive engineers.
                           
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