What mileage does your slant six powered ride get?

Slant 6 Engines

  1. Garys72Duster

    Garys72Duster Well-Known Member

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    Yea, the mid 60s Mobile economy runs. That's when they were getting concerned about fuel economy, as gasoline prices were soaring past .15 a gallon! LOL
     
  2. doc540

    doc540 Well-Known Member

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    Mileage reconfirmed:

    50 miles
    65mph
    filled and refilled from the same pump
    speedo correct
    225 Slant
    mild Clifford cam
    Clifford intake and shorty headers
    Holley 390
    A904 auto
    2.76 gear
    185-70-13 tires
    non ethanol 91 octane

    24.5mpg

    slantsixdan suggested I put a tad more timing back into it

    as usual, he was right

    plug #5

    lancer plug best1.jpg


    Slantsix64, I'm your huckleberry :)

    doc holiday7.jpg
     
    Last edited: Jan 8, 2019
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    • Slantsix64

      Slantsix64 Well-Known Member

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      Hold up there buddy, have you gotten a recurve on your Dizzy? What rpm range is all your timing coming in at IN,Mech,Vac?
       
    • doc540

      doc540 Well-Known Member

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      Slant's turning about 2600 rpm at 65 mph, so I'm not sure about the timing right there.

      Stock '68 distributor w/Pertronix point eliminator kit, no recurve, no spring changes, no timing light.

      Just an old gearhead's ear.

      He's in assisted living now, but he can still hear good. :)
       
      Last edited: Jan 9, 2019
    • KosmicKuda

      KosmicKuda FABO Gold Member FABO Gold Member

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      Actually I think it was more the mind set of the people buying these cars new, my parents for instance. That generation grew up in the great depression and could be somewhat frugal.

      I think it was valuable PR for car manufacturers to claim they won the Mobil Economy Run because that generation was listening.

      I think my dad had 4 different cars with /6 power over the years. I still remember them shopping for a new car and I actually talked them into buying a new 1967 Dodge Coronet 440 white hat special with a 318!! Only V-8 they ever owned.
       
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      • Garys72Duster

        Garys72Duster Well-Known Member

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        Yep, my Dad had a slant 6 in a Valiant. Ran great, and good on gas. My parents frugal ways got transferred to me. LOL. So we're still living with the save a penney mindset. Anybody have a cheap 383 intake for sale? Ha!
         
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        • GenLee1970

          GenLee1970 Well-Known Member

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          In the fall 2016 I did a 5 week cross country trip (that included Route 66 ) from RI to California, part way up the Pacific Coast Highway then to Minnesota then home.
          73 Dart with 1971 225, 2.76 rear, 904 trans, Holley 1920, points ignition, timing at 5 degrees, 205 75 14's. Car loaded with tools, parts, camping gear, survival gear etc.
          Temps ranged from high 70's (southern portion) to 10 degrees (through Wyoming en route to Minnesota). Highway driving ranged from 55 to 70 mph. Lots of back road and city driving on Route 66 including 5 hours in LA traffic. Lots of hills and time spent at elevation car was not tuned for.
          8,360 miles total. Average at the end of the trip was 19.7 mpg. Best reading was 21.9, worst was 13 in LA (lots of time idling then accelerating for an 1/8 mile to the next light so I could idle some more, accelerate, idle, repeat.)
           
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          • Killer6

            Killer6 Well-Known Member

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            '72 Swinger w/ A/C, 8.75 rear, 3.55SG, stock converter, 235/60r14's, 9.3:1 CR, 276/.490 DC cam, Holley 2245 2bbl, 6-1 header & 2.5" exh. , Combined MPG was 18.
             
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            • aaronk785

              aaronk785 Well-Known Member

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              About 15 years ago my mom came up from Mississippi in her 73 slant dart. It wasn't running well to I tuned it up for her. Don't remember where I set the timing but I rebuilt the carb, put on new wires and plugs. On her way back home she swears she got 32 mpg. These were all highway miles and she never drove over 50mph. She was a nightmare on the interstate. I guess its possible.
               
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              • a12

                a12 Well-Known Member

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                pinochio.jpg
                 
              • a12

                a12 Well-Known Member

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                • Killer6

                  Killer6 Well-Known Member

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                  Sorry Sport, but that's a fact. And it's not that good, My
                  '69 dart w/a Blazer cammed 318, 4spd & 3.23's got.....
                  18MPG combined.....and was a good second+ faster.....
                   
                • Killer6

                  Killer6 Well-Known Member

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                  I'll follow that with when I chucked the 4.11's in it the MPG promptly dropped to 12-13.........
                   
                • RAT ROD AL

                  RAT ROD AL I know just enough to be dangerous FABO Gold Member

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                  I get any where from 11 to 14 mpg . 904, 3.23s. 28" tires on back in my van.
                   
                • arvz@cyber-dyne

                  arvz@cyber-dyne New Member

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                  '65 Valiant V200 wagon, with virtually the entire innards of several '76 4-doors transplanted into it: 8.25" 3.23 rear end, A-833 OD 4-speed, stock '81 225 with Carter BBD two-barrel manifold, custom hot advance curve, MSD 6A ignition and coil (surprise, way better than the stock box!), Bosch plugs, 1 7/8" exhaust system, dual-circuit brakes with the '76 control arms and disc brakes, 340 torsion bars, front and rear sway bars, KYB shocks, extra leaf and overload springs on the back because I carried tools and parts a lot, synthetic lubes, top-cylinder lube in the gas, 44 psi radials at 38-44 psi depending on the load, full thrust alignment with less toe-in and more caster. 1994-2015 I drove this remanufactured rig about 340K miles in Oregon, Washington, Idaho, and Montana, mostly energy-efficiency related audits and research projects. Correcting for speedo error, multiple fill-ups: standard highway mileage was ~25 MPG. If I kept the speed under 55 mph for the whole trip, it would do ~27 MPG.

                  At an apartment complex energy audit on the Oregon coast, I met a retired Chrysler engineer who saw my car and when I told him what running gear I had, he said, "25 MPG, right? That's what we designed the cam to do!"

                  That '65 wagon rusted away after 50 years as a daily driver. After I retired I did another complete parts transplant into a very pretty '64 V200 wagon a friend gave me, so now that running gear with 340K miles since the original overhaul is in another car. The A-833 (extra ATF to cover the top bearing) and rear axle seem fine, that '81 engine has normal compression and oil pressure (although I did put another head on because of valve seal problems, and a new cam chain set at ~260K, it ran fine although the highway gas mileage had fallen to `22 mpg). I used the 225 that was in the '64 because it only had 120K on it. The '64 is still major fun to drive, and I put a set of Wheel Vintique 6x15 Rallye wheels with 185/65/15 Continental True Grips on it recently. These look like the largest tires you can run on a 64-66 without any rubbing at all, and should be available for awhile because the '06 Prius generation uses this size. Seems like it is getting hard to find top-end tires in 14" sizes. In 2016 this specific Continental out-performed the Michelins in on-vehicle tests, but I should say Michelin tires saved my bacon many times. I always had to show up for appointments with no regard to the weather or season. I never regret spending a few extra bucks for the best tire I can find. Nokians usually end up on top these days.

                  Irrelevant to the good gas mileage, but the '65 still has the stock AM radio, which has a great tuner section that would pull in stations these modern phase-locked-loop radios can't even find. Here is a tip for the generations: in the old AM car radios the main output transistor is often ballasted by the radio light bulb. When the light bulb burns out, the main output transistor burns out and the radio dies. So you can find a new Si output transistor with bulletproof specs and solder it into the circuit board, replace the light bulb, and the radio will last 50 years at least.

                  65 Valiant w-mags (1).jpg
                   
                • valiantwagonguy

                  valiantwagonguy Well-Known Member

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                  My 65 Valiant wagon with a 170 with a 4 speed from a 65 Barracuda with 1to1 final drive and 323 rear gets around 24 on the highway fully loaded with all my camping gear and tools ( lots of weight) A 225 in the same car with the same set up got around 18.
                   
                • Aaron65

                  Aaron65 Well-Known Member

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                  That's amazing how much better the 170 does on the highway. Your experience with the 225 mirrors mine; I get around 18 or so on the highway, but my car originally had a worn out 170. I guess the little bit of extra power is a fair enough tradeoff.
                   
                • valiantwagonguy

                  valiantwagonguy Well-Known Member

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                  170's are the greatest little motors for a driver.With a 4 speed behind it (not an overdrive one) they are lots of fun to drive. That little short stroke motor is very responsive when you set it up with the right trans and rear.
                   
                • 66fs

                  66fs FABO Gold Member FABO Gold Member

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                  I'll agree with that. I had a souped up 170 behind a O/D manual in a 64 Barracuda. Ran great, unbelievable mpg and good power.
                   
                • my68barracuda

                  my68barracuda Well-Known Member

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                  Slant powered 1983 D150 towing the slant powered 1968 Barracuda to a race.

                  The slant in the D150 was built for low rpm torque. It has 3.73 rear gears in a 8.25 differential. A833 OD tranny. Holley 2 bbl 2280 carb, dual Dutra's, free flowing exhaust, HEI ignition, cold air intake to the carb, electric fan,,,,

                  When towing on level ground running 65 mph AC and cruse on it will easily get 15 mpg. In hilly terrain/mountains, the mpg and the speed drop, a lot.

                  The towing is helped by the lightweight aluminum trailer and the Barracuda being totally stripped out inside.

                  When running solo the D150 will get 20 mpg, if I stay in the right lane on the highway at 65 MPH or below.
                  Run in the left lane 70 to 75 + and the MPG drops to the 16 to 17 range. These trucks are aerodynamic bricks.

                  In town / stop and go driving it gets 15 to 16 mpg.

                  A2050A59-EB0A-4678-A59D-3933CB3FFEC2.jpeg
                   
                  Last edited: Mar 18, 2020
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                  • MCPObr44

                    MCPObr44 Well-Known Member

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                    I get in the area of 24 miles to the gallon in my stockish 71 valiant 4 door. I say stockish, because it's got a pertronix ignitor.

                    The way I measured is by knowing a fixed distance between two points (not city driving), and filling my tank up immediately at the beginning and end of the trip. So I know I'm 100% full when I start, and I know exactly how much fuel it takes to make me full again (spilling out the fill hole).

                    It's consistent too. I've done it multiple times. I kept receipts while doing it. None of it relies on the speedo, odometer, or fuel gauge.
                     
                  • Nigel Hely

                    Nigel Hely 64DartDownUnder FABO Gold Member

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                    Damn! I only just threw out all my calculations the other day, we had done a long trip, I recorded all the details... 1964 Dart GT, stock 225, automatic, 2.93 diff gears, 2 1/4" exhaust, 225/60/14 tyres.
                    The end result over about 350 miles of highway/country roads driving was average about 23.1mpg (19.68L/100km). Note: that's using real-deal UK Gallons, not "Diet Gallons" HaHaHa!
                     
                  • moparblood

                    moparblood Well-Known Member

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                    just starting driving my Dartlite, so far 26.6 mpg's on average (highway) i will soon start tweaking, and give up date.
                     
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