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1978 Impala motors

Discussion in 'The Hokey Ass Message Board' started by Doc Squat, Oct 23, 2011.

  1. Doc Squat
    Joined: Apr 17, 2008
    Posts: 1,375

    Doc Squat
    Member
    from tulsa, ok

    What motors did Chevy put in 1978 Impala. Were there any problems with any certain motors. I'm thinking about buying one that was taken out of a running 1978 Impala. I'm told its a 350. How do I go about finding the #'s to identify it as a 350?
     
  2. Mike Rotch
    Joined: Jul 15, 2010
    Posts: 166

    Mike Rotch
    Member
    from Easley SC

    look on the left side of the block, behind the head and between the trans. Should be a set of #'s running parallel to the trans case, then look them up here:
    http://www.nastyz28.com/sbchevy/sblock.php
    or by doing a google search.
    For example a 78 350 from a car would/could be "366245".
     
  3. sumo
    Joined: Sep 28, 2002
    Posts: 83

    sumo
    Member

    There are numbers stamped into front the block on the passenger side on the head surface, you may have to scrape the grease and gunk off to see them they will be very small, the numbers are coded to indicate horsepower exact year of production and vehicle it came out of. the casting numbers on the rear of the block are a basic indication of what it is.
     
  4. scottlep
    Joined: Sep 1, 2010
    Posts: 109

    scottlep
    Member

    A '78 350 is gonna be a pretty low horsepower smog engine. Even if you rebuild it it still will have smog heads, etc. These days you can buy a decent 350 crate motor from Jegs or Summit for like $1300. Way cheaper than rebuilding the Impala engine.
     

  5. some years had the 5.0 305 or 5.7 350 stamped on the rear deck drivers side head with other number like 397001 something like that they are big enough to see them
     
  6. Doc Squat
    Joined: Apr 17, 2008
    Posts: 1,375

    Doc Squat
    Member
    from tulsa, ok

    I can get the motor for $100.00 What do you all think is should cost to go through the motor and put new rings and bearings in it?
     
  7. BigJim394
    Joined: Jan 21, 2002
    Posts: 760

    BigJim394
    Member

    "It depends"
    You will have to see what condition the engine is in. Can you just put rings in after a quick hone, or are the pistons worn and you need to bore the block and get new pistons and rings? Maybe you can just put in a new set of bearings and maybe you will find wear problems on the mains and need to get the crank turned. You never know until you internally inspect the engine. You will need an engine gasket kit, and if the engine has some miles on it, you'd probably want to put a new old pump and timing chain in it while its all apart.
     
  8. Deuces
    Joined: Nov 3, 2009
    Posts: 19,916

    Deuces
    Member
    from Michigan

    Every one I've seen came with 305's.... I was able to tell by looking at the hollowed out harmonic balancer that chevy used back then.... And the light blue paint... Gag! :eek:
     
  9. bryan6902
    Joined: May 5, 2008
    Posts: 1,137

    bryan6902
    Member

    My dad had a 78 Caprice, same thing, with a 350. It ended up flattening lobes on the camshaft. Don't blame non-zinc oil, this was almost 20 years ago. I believe this was an issue with this era SBC, apparently they used a softer alloy or a different heat treating process.

    Ring & bearing rebuild isn't a bad way to go if you want to keep it cheap. You can probably buy decent parts and keep it under $500. But be prepared to spend some money just in case your 'running' 350 has some issues once you tear into it...
     
  10. Sqeaky Hinge
    Joined: Oct 10, 2011
    Posts: 303

    Sqeaky Hinge
    Member

    On the driver's side of the engine block , at the back of the engine , you'll see a set of numbers...the following number are the ones you'll problably see:361979= '76-79 305 cu.in.----366245='78-'82 350 cu. in.----330817='70-'80 400[​IMG]cu.in.
     
  11. you said it's from a running car, is there any issues with it?do you plan to up grade it, if not just run it as is. a friend has a 350 that sat in a shed for 10yrs installed it in a 57 chev pu daily driver has been on the road for 3yrs has only changed the gas pump this summer.
     
  12. Blue One
    Joined: Feb 6, 2010
    Posts: 11,016

    Blue One
    ALLIANCE MEMBER
    from Alberta


    If that $100 engine has seen as many miles as is typical for a 1978 car then it will need a rebuild, not just rings and bearings.

    When you get down to that with machine work and parts your $100 engine is not such a bargain any more.

    I recently bought a brand new in the crate GM 350 290HP engine from a local GM dealer for $1800.

    You could spend more than that on your $100 engine very easily.
     
  13. Sqeaky Hinge
    Joined: Oct 10, 2011
    Posts: 303

    Sqeaky Hinge
    Member

    in addition there are these numbers you may see on the back of a '78 Impala engine: #460703='78 350 cu.in. , #460776='76-'78 305 cu. in. , #460777='76-'78 305 cu. in. , #460778='76-'78 305 cu. in. , #471511= '79-'82 267 cu. in. , #3914678='68-'79 350 cu. in. , #3932388= '68-'79 350 cu. in. , #3951509= '70-'80 400 cu. in. , #3951511= '70-'80 400 cu. in. , #3956618= '68-'79 350 cu. in. , #3970010= '69-'79 350 cu. in , #3970014= '68-'79 350 cu. in........I hope this helps , I keep this little book with me everywhere I go , just in case I find one worth saving....
     
  14. YOu might have a 267 V8, also. Looks just like a 350 from the outside. It's even worse than a 305. A true boat anchor. Damn near anyone selling a SBC claims it's a 350, when in reality, most are not.
     
  15. $100 is less than a you-pick yard gets for one, so the price is right. Compression test it and see how it does. If the compression is good, stick it in and run it. Put a new oil pump and some new gaskets on it and forget about it. If anything seems suspect, then pass on it.
     
  16. squirrel
    Joined: Sep 23, 2004
    Posts: 48,236

    squirrel
    Member

    uhhh...not quite. Chevy didn't put a 267 or a 400 in a 78 impala.

    Look at the damper, if it's the wide one it's likely a 305. But the letter code stamped on the block (under the alternator) will tell you for sure what it is. Also it's possible the engine was swapped some time in the past 33 years.
     
  17. Sqeaky Hinge
    Joined: Oct 10, 2011
    Posts: 303

    Sqeaky Hinge
    Member

    www.chevymania.com mabye you should check this out , it has a wealth of info , and it may not have come in a '78 Impala , but , I just threw some casting numbers out there for mid-to late '70's engine blocks , in case the motor had been changed somewhere in life....:)
     
  18. Doc Squat
    Joined: Apr 17, 2008
    Posts: 1,375

    Doc Squat
    Member
    from tulsa, ok

    Thanks all. Great information and help. I think I'll just cough up for a 350 crate motor.
    Thanks.
     
  19. Pir8Darryl
    Joined: Jan 9, 2008
    Posts: 2,488

    Pir8Darryl
    Member

    Avoid that 267 like the plague. It's an absolute turd. None of the internal parts are good enough to be used to build anything that even resembles performance..
     
  20. Jay.S
    Joined: Feb 24, 2009
    Posts: 372

    Jay.S
    Member

    ^^^^ I agree 267's are TRASH!! as for a running 78 350. its a small block chevy, i have use countless motors from this era, all they need is a gasket set and they will run great for another 15 years. No need to spend unessesary money. If the engine goes in a couple of years then replace it. The number on the back of the block is 3970010, which specifies 350. Since it is a late 70's car 350, it will be a two bolt main block as well.
     
  21. Deuces
    Joined: Nov 3, 2009
    Posts: 19,916

    Deuces
    Member
    from Michigan

    What was the stroke length on a 267???
    3.100"???
    You could build a de-stroked 350 motor with that crank.... 4.030" bore x 3.100" stroke = 316.34ci...
    That make a cool little street motor..:) Good on gas with a "little" zip!;)
     
    Last edited: Oct 25, 2011
  22. Deuces
    Joined: Nov 3, 2009
    Posts: 19,916

    Deuces
    Member
    from Michigan

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