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Chevy 427 Mystery Motors

Discussion in 'The Hokey Ass Message Board' started by 2club, Oct 13, 2012.

  1. 2club
    Joined: Feb 2, 2011
    Posts: 26

    2club
    Member
    from California

    Anybody see the article about the Chevy 427 Mystery Motors over at
    hotrodenginetech.com I thought they were all 427s and never realized that they actually made three different sizes. Does anyone know anybody who has one of these motors or any parts fromthem?
     
  2. Mark Hinds
    Joined: Feb 20, 2009
    Posts: 606

    Mark Hinds
    Member
    from pomona ca

    I saw what is suppose to be a 427 mystery motor at the NHRA museum in Pomona.
     
  3. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,304

    henryj1951
    Member
    from USA

    Z-11's come to mind...

    :cool:
     
  4. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,304

    henryj1951
    Member
    from USA


  5. oldblu65
    Joined: Jan 29, 2009
    Posts: 121

    oldblu65
    Member
    from Tennessee

    I have an 1965 issue of Hot Rod magazine that has an article on the mystery 427 Chevy motor . I have it stored " somewhere " and would have to find it !
     
  6. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,304

    henryj1951
    Member
    from USA

  7. greg32
    Joined: Jun 21, 2007
    Posts: 2,113

    greg32
    Member
    from Indiana

    Big block, replacing the 409 and 427 version of the 409. Offered in late 1965 in chevelles and full size cars. Had one of the early 396s in a 66 impala.
     
  8. Smokey Yunick comes to mind anytime I read mystery and Chevy in the same sentence. Grab a copy of Smokey's Autobiography and you should find an interesting article about the Mystery 427.
     
  9. shawnspeed
    Joined: Sep 10, 2009
    Posts: 165

    shawnspeed
    Member
    from Attica Mi

    Dad bought a couple of cars through a friend that was an Engineer at the GM tech center back in the mid to late 60's ...the first one was a '62 Biscayne with a 409 "mystery " engine in it...1 1/4 " Hy-tuff axels lightened sheetmetal , a big for the day mechanical cam , that liked to break valvesprings....leading him to sell the car...and get one of the first '68 rs/ss camaros with the famed dz 302 package..from the same guy...near as he could tell , both of these cars were test "mules" that they would sell to the employees after the test was done....a common practice back then before lawrers got involved....somwhere in the early '70's they shut down the employee purchase of parts from test/ experimental vehicles , when someone sold a set of tires to his neighbor , that came off a experimental vehicle, but were no different than what was available at the local garage..IE they were not experimental tires...none the less , a tire failure occored on this "used tire" a lawsuit ensued...and you guessed it no more , cheap ,low use parts available to employees...the program was shut down , and now ANYTHING associated with a test or prototype is destroyed and sold for scrap , in unusable condition ....even if it is carrover production material....Oh well ...damm lawers will be the death of us all ...litigating us into non-existance...Shawn
     
  10. mtkawboy
    Joined: Feb 12, 2007
    Posts: 1,213

    mtkawboy
    Member

    I snuck into the pits at the 1964 Daytona race week. Bobby Allison had one of these motors in his sportsman Chevelle but we didnt know what it was at the time. I also saw Smokey Yunick seating the rings of a new 421 Pontiac by dusting a can of Bon Ami cleanser over the top of the carbs with the engine turning 6 grand but thats another story
     
  11. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    tommy
    Member Emeritus

    [​IMG]
    [​IMG]

    This is not the same engine used in the 65 Chevrolets. They used the 65 427s with the regular BB valve covers.(note the valve cover) I have a buddy that has one of the Z-16 427 Chevelles One of the original 201 factory Z-16s Lots of clones but only 201 factory cars. I know this is OT but if you put one in a hotrod everyone would think it's just a 348 or a 409. A big waste of a big buck engine.

    Edit the 427 came out in 1966 the Z-16 used a 396 425 Corvette motor in 1965.
     
    Last edited: Oct 16, 2012
  12. terryble
    Joined: Sep 25, 2008
    Posts: 541

    terryble
    Member
    from canada

    What exactly is the difference between a 409 and the 427 Mystery Motor besides the obvious 18 cubic inches (ahead of the smart asses).
     
  13. kyvetteman
    Joined: May 13, 2012
    Posts: 760

    kyvetteman
    Member

    The "W" head configuration of the 348's and 409's was a carryover of the original 427's as shown in the pic of the Z11 427 in the '63 Impala above.
     
  14. 1971BB427
    Joined: Mar 6, 2010
    Posts: 7,055

    1971BB427
    Member
    from Oregon

    If you had a '66 Impala 396, it wasn't one of "the early " ones! The 396 came out in 1965 as an option in Impalas. I had a '65 SS 396 Impala.
     
  15. Larry T
    Joined: Nov 24, 2004
    Posts: 7,676

    Larry T
    Member

    It was a mid year change in the Impalas. Early 65 Impalas had 409s as the top of the line engine.

    But the canted valve (396 style) Mystery Motor was used in 1963.
     
  16. greg32
    Joined: Jun 21, 2007
    Posts: 2,113

    greg32
    Member
    from Indiana

    Ok, but you could also get a 396 in a chevelle, think it was a Z 16 option, but its been a while, so I may be wrong. Traded the 66 Impala for a 67 SS427 Impala, traded that for a LS6 70 chevelle. Wish I had all three today, but I like my steel 32 ford more.
     
  17. terryble
    Joined: Sep 25, 2008
    Posts: 541

    terryble
    Member
    from canada

    Sorry but I remain confused the car featured in the photo on page 11 clearly says 427 on the side and the motor is a W motor. How did the 409 become a 427, bore, stroke or both? Can you make a 409 into a 427?
     
  18. biscaynes
    Joined: Mar 16, 2008
    Posts: 1,649

    biscaynes
    Member

    stroked to 427
     
  19. models916
    Joined: Apr 19, 2012
    Posts: 380

    models916
    Member

    Mystery Motor in Jr's 1963 stocker was a stroked crank with the new BB heads. NOT a Z-11 motor Z-11 was a stroked 409 with tall port heads, drag motor for the 1963 Impala with all the aluminum stuff. Original Mystery Motor had more head bolts and lots of other unique parts than the upcomming 396, but did look very similar.
     
  20. jimdillon
    Joined: Dec 6, 2005
    Posts: 3,143

    jimdillon
    Member

    Here is a pic of Hank gathers 63 Z11 that I took at Meadowbrook in 2006 I believe. Probably one of the best sounding camshafts I have ever heard in a car of this vintage. I am quite sure Hank told me that the heads were a bit taller, but different for sure than the 409 heads. As I understood the crank, pistons and rods were all different and special pieces as well.

    Also are some pics of what I believe is the 63 mystery motor I saw and copied off of the internet. I am quite sure GM has one of the mystery motors in their collection on a stand. I read a card on the engine which gave some of the details. Somewhere I think I have a pic I took. You will note the porcupine look to the heads but of course these heads are a bit unique.-Jim

    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
     
  21. Muscle Cars?!?! :confused:

    Thought they were off topic??? :confused:

    I guess only if they are a '65 GTO. :rolleyes:
     
  22. 2club
    Joined: Feb 2, 2011
    Posts: 26

    2club
    Member
    from California

    Part 2 of the Chevy Mystery Motor story was posted at:

    http://hotrodenginetech.com/mystery-motor-development-engineer-bill-howell-tells-all/

    It is an interview with the test and development engineer Bill Howell, who did all the mystery motor development testing. There's some good new information and some good intake pictures plus the accompanying photo of Rex White in one of the factory test cars used to test the engines at the GM proving Grounds in Mesa, Arizona prior to the 1963 Daytona 500. Good read!
     

    Attached Files:

  23. Deuces
    Joined: Nov 3, 2009
    Posts: 21,310

    Deuces
    Member
    from Michigan

    Correction: The Z-16 option 396 was rated @ 375 h.p.
    It's the L-78 396 motor....;)
    The only cars to get the 396/425 motor was the '65 Vette and a couple of '65 Impalas...
     
  24. Thunderroad312
    Joined: Nov 18, 2012
    Posts: 158

    Thunderroad312
    Member

    Hot Rod Magazine Yearbook #3 circa 1963 has a complete breakdown on the differences with pics. The "mystery motor" was the precurser to the modern "porcupine" head big block of today. It was allowed to run NASCAR but there were none sold to the public. Race teams only.There was also a 427 inch High port racing only version of the 409 W motor. Both engines share the same bore spacing and cranskshafts can be swapped but the big difference is that the W series motors have a 74 degree deck angle with the combustion chamber in the top of the cylinders, and the mystery motor has a 90 degree deck angle with the chambers in the heads.
     
  25. like Biscaynes said - it was the crank and stroke of the orginal 409 W motor that made it a 427 - my buddy was lucky to find one for one of his 409 builds...and it ran best with a single 4 barrel Nascar intake....
     
  26. Brad54
    Joined: Apr 15, 2004
    Posts: 6,015

    Brad54
    Member
    from Atl Ga

    That actually ended up being an over-the-counter PART NUMBER for Chevy 396 engines... they had a problem with the rings seating, and the official fix was a little GM Parts box with a can of Bon Ami and an instruction sheet.

    -Brad
     
  27. All very interesting reading. My hat is off to Mitech on their website for having a tech page with this kind of info from the actual players involved. Great job Mike.
     
  28. lawman
    Joined: Sep 19, 2006
    Posts: 2,665

    lawman
    Member

    Lot's of good info Fellow's.
     

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