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Help with 1980 Chevy Inline 6

Discussion in 'The Garage' started by lifethroughdeath, Nov 9, 2004.

  1. lifethroughdeath

    lifethroughdeath 1/2 ton status

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    Hey guys I need your knowledge, whats the avg mpg on a 1980 Chevrolet Van with a 250(i think)I6 ? And any info on the motor that you'd like to share, good, bad, how long do they usually last, etc... Thanks in advance

    Nate /forums/images/graemlins/k5.gif
     
  2. big pappa b

    big pappa b 3/4 ton status

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    My 80 K5 came with the straight 6. The odometer had 86K on it. Could be 186 for all I know. But it was ruuning fine until it blew a head gasket. Didn't feel like messing with it so I out in a 454 /forums/images/graemlins/peace.gif I did notice the exhaust manifold ws cracked and hear they have a bad reputation for that
     
  3. divorced

    divorced 3/4 ton status

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    [ QUOTE ]
    whats the avg mpg on a 1980 Chevrolet Van with a 250(i think)I6

    [/ QUOTE ]

    I didn't have a van, but did have have an 81 C10 with a 250 6 cylinder, 3 speed manual, 2.73 gears, and 235/75-15 tires and was getting 23 mpg. The 250's with the integral head have problems with cracking, mine was fine though. I wish I still had the truck, a cop hit it during a police chase (my truck was parked) and it was totaled. /forums/images/graemlins/angryfire.gif
     
  4. ronnny3

    ronnny3 Registered Member

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    It was explained to me by someone at work that the inline six had it's down fall in the late 70's or early 80's from emmisions before fuel injection came along with the fuel running lean on the one and sixth cylinders. The motors are durable with the exception of like some said the manifolds etc... . When it comes to bearing there are seven for six cylinders while on a v8 there are 5 for 8 cylinders. Also the longer stroke of the inline is always more tourqe forthe cubic inch. But is not good for high horse power. just think about chevy now going to an i-5 and something about maybe a 6 agian. Just my thoughts.
     
  5. atho

    atho 1/2 ton status

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    [ QUOTE ]
    just think about chevy now going to an i-5 and something about maybe a 6 agian. Just my thoughts.

    [/ QUOTE ]

    Chevy Trailblazer...4.2L L6 /forums/images/graemlins/waytogo.gif
     
  6. bigblock44k5

    bigblock44k5 1/2 ton status

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    I6 is a great engine, will last a helluva long time with barely any maintenance. Ronnie is close with the emmisions statement. The reason for poor emissions is due to the long travel of the intake runners for the outer cylinders. The fuel that eventually makes it to these cylinders are larger droplets so they dont burn as efficiently. Other than the fact that these engines sound like they are going to blow up past 4500 RPM, they really are good engines with good torque for their size. There are also many performance parts available, such as a header, intake, cams, and so forth. Also, a V8 will swap in directly in its place with no mods. It will bolt to the same tranny and motor mounts.
     
  7. diesel4me

    diesel4me 1 ton status Premium Member

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    My 81 G10 van began life with a 250 "camel humper" six,it had the 2 barrel "Vari-Jet"carb(I called it a "Very Junk"!--always had a hesitation upon acceleration,no matter what I did)-it had the lock up TH350 tranny,it got 15-19 mpg when I first got it in 1990,when they started using oxogenated fuel it dropped to 11-14 mpg--it had 3.08 gears,but the rear differential case got hogged out by the side gears at 146,000 miles so I swapped in a boneyard replacement,that unfortunately had 2.73 gears--can you say DDDAAAAWWWWWGGGGG!--I think the six was faster than the 307 V8 I swapped into it--had more low end tourque,the 307 is a gutless wonder until you wind it up to 3000 rpm or more.
    My 79 C10 had the same integral head 2 barrel 250 six until recently,when it decided to lose a chunk off the top of the #6 piston for some unknown reason,at only 116,000 miles.I had adapted a 600 cfm edelbrock carb onto it with a custom carb adapter,that solved any hesitation problems(it ran exactly like the van did--must be an emission related problem,running too lean).It ran very well for two years until the piston broke.I like the early sixes with the removeable intakes and one barrel carbs much better,they are much more rugged--the "camel humpers"were noted for cracking heads,exhaust manifolds,and drivability problems due to the goofy carb and emission controls,and spark knock,I think thats what killed my piston- but I didnt have much trouble with mine in the van,and I even drove it to TN wide open for 14 hrs straight at 85+ mph and it got 14 mpg.My 79 C10 now has a 305 from an 86 van in it--it goes like hell now compared to the six,at least when its empty--and it gets better mpg by 2 or 3 mpg too.If I ever own another chevy six,I'd want it to be the older version with the non-integral head and a one barrel-you can put four barrel intakes and headers on those motors. Or a 235 from the 55-62 trucks,the best chevy six ever made!-But I have found it easier and cheaper to upgrade to a V8--a big block is nice if you can find one reasonable! /forums/images/graemlins/grin.gif
     

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