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Technical How to identify Olds 350 or 455?

Discussion in 'The Hokey Ass Message Board' started by MrFlash, Aug 27, 2020.

  1. MrFlash
    Joined: Aug 24, 2019
    Posts: 7


    I'm a Ford guy, so I cant just look at an Olds engine and tell you exactly what it is.

    My friend has a 72 Cutlass.
    He says it has an original "rocket" engine but doesn't know the displacement.
    Is there an easy way to just look at the engine and know which it is?
    Or are all the Olds blocks the same?

    He wants an Edelbrock intake manifold for it.
    I just want to make sure he orders the right one.
  2. lostone
    Joined: Oct 13, 2013
    Posts: 1,540

    from kansas

    I'd bet looking up the engine code should tell him.

    With that said.... My old age will kick in now and I must admit its been 30 yrs since I played with olds and I don't remember where the code is !! I think on the front of the block under head seam.
  3. junkman8888
    Joined: Jan 28, 2009
    Posts: 582


    For a question like this, the internet is your friend, I looked up "Oldsmobile engine identification" and found a number of charts that will give you the information you're looking for, also, check out the engine identification videos so you'll know where the information is located on the engine block..
    egads likes this.
  4. upload_2020-8-27_12-45-6.jpeg

    Olds 350 1972 ^^^^^


    Olds 455 1972

    looks like the easiest is the oil filler neck. I am pretty sure that they were different blocks and the only '72 350s I have ever seen stock were 2 bbl motors. That don't mean they didn't come with a 4 bbl I have just never seen one.
    dana barlow likes this.

    Joined: Feb 16, 2016
    Posts: 87


    455 is wider than a 350. Intake or block casting number would be a simple non-Olds-guy way to quickly figure it out.
  6. KevKo
    Joined: Jun 25, 2009
    Posts: 548

    from Motown

    Yeah, they all look the same. Check between the intake and water pump. Casting number should be there.
  7. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 7,526

    Bandit Billy

    This is a '68 455
    Easier to identify from this angle. It is a rocket! NASA's likely gets better mileage though.
  8. DDDenny
    Joined: Feb 6, 2015
    Posts: 14,637

    from oregon

    Don't know much about them other than the 425 that the previous owner put in a 64 Chevelle two door wagon I had many years ago, what a dog that thing was, car had a Muncie 4 speed and a 4.11 twelve bolt also, it revved to 5 grand and said "I give".
  9. wheeldog57
    Joined: Dec 6, 2013
    Posts: 1,956


    20190525_072308.jpg 20190705_113422.jpg The 455 is quite a bit wider than the 350 20190525_072308.jpg
    1970 455
    jimmy six likes this.
  10. Fordors
    Joined: Sep 22, 2016
    Posts: 3,411


    Easiest way I know is to measure the width of the intake manifold. If it’s about 14” it is a 455.
    Oh, and @porknbeaner , I had a ‘73 Cutlass, 350 4 bbl, factory 4 speed. Four barrel 350 Oldsmobiles were never unusual even in the smog years.
    jimmy six likes this.
  11. wheeldog57
    Joined: Dec 6, 2013
    Posts: 1,956


    Ok, I made a mistake on my last post. I tried to edit and made is worse. . . .
    Crispy looking engine is 70 455
    The other is early 70s 455
    Pictures for information purposes only as we know pre 1965 only on this site.
    Also note Oldsmobile made a 330, 400, 425, 430ci and they are also tough to differentiate from one another. Check your numbers on the front pad above the water pump
  12. jimmy six
    Joined: Mar 21, 2006
    Posts: 8,541

    jimmy six

    The big one is wider as said above..
  13. Wrench97
    Joined: Jan 29, 2020
    Posts: 342


    Back in the day the 350 and 400 were gold and the 455 blue, not very scientific but depending on how original it is.
    I don't recall a lot 455's in a cutlass only 442's and wagons.
  14. chubbie
    Joined: Jan 14, 2009
    Posts: 2,311


    330-350 were gold, and had a number left of the #1 spark plug. tall decks had a letter left of the number one spark plug. tall decks were red till???'72 maybe then the 455's were blue. The 400 was bronze NOT GOLD! So what color is it? and is it a number or a letter......
  15. oldsjoe
    Joined: May 2, 2011
    Posts: 2,535


  16. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 8,687


    I recall that 455 has a taller deck height (approx. 1") to a 350, similar to differences between a 351W and 302W along with a wider intake manifold (approx 2"). SBO & BBO heads are interchangeable however valve sizes are different. Here's an engine decoder that may assist.

    Attached Files:

  17. Funny I seldom saw them and was tuning to augment my wages in the smog years. I guess it could be that back then most people who owned stick shift 4 barrel cars tuned their own.
    Deuces likes this.
  18. sunbeam
    Joined: Oct 22, 2010
    Posts: 5,169


    Deck Height 350 is 9.3 455 10.6
    Deuces likes this.
  19. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 1,848

    from Brooks Ky

    Might want to get a copy of this so you can familiarize yourself with whats what.........
    Look on Amazon

    Olds Book.jpg
    Deuces and chevy57dude like this.
  20. MrFlash
    Joined: Aug 24, 2019
    Posts: 7


    Thanks everybody.
    We’ve narrowed it down to 350 block from 1970.
    Now to identify the heads.

    Does anyone know what ratio the rocker arms are supposed to be?
    1.5 or 1.6 ?

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