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Technical Chevy 302

Discussion in 'The Hokey Ass Message Board' started by 46poncho, Jun 28, 2019.

  1. 46poncho
    Joined: May 24, 2009
    Posts: 148

    46poncho
    Member
    from Indiana

    A friend picked up what is supposed to be a 302 chevy engine. I have not seen it yet. He told me it is a 1968, 3970010 block, 2 bolt main, 1031dz. I have looked at multiple sites and talked to people, some sites say dz is 69 only, some say 67-69 are 4 bolt main, other say 67 and 68 are 2 bolt and 69 is 4 bolt. How do we know what he has??? One guy said it is not a real 302!!!
    Thanks

    Sent from my SM-S327VL using The H.A.M.B. mobile app
     
    Deuces likes this.
  2. jnaki
    Joined: Jan 1, 2015
    Posts: 3,373

    jnaki





    Hello,

    When we were first married, our next door neighbor was another young couple with a giant, Rhodesian Ridgeback. They were a happy-go-lucky couple and their dog was ever so lucky to be able to ride around in a dark green/white striped 1968 Z-28 Camaro. That car was stunning and the back seat was taken up with this giant of a dog, daily.

    What got to me was that with all of the big Chevy motors floating around, why would the factory put in such a small motor in this newish car? a 302? Well, after several drives in it with our neighbor, that car was light, super fast and sounded just as healthy as a bigger 396/427 motors. It was a car that gave off plenty of envy for us 20 something folks and that lucky Ridgeback riding in the back seat.

    So, your 302 could have been one of these motors just floating around after all of these years. No one that I knew specifically made a 302. An 1/8 over 283 was a 301 and a very common build, but not known as a 302. So, from the outside, it is a small block Chevy.

    Jnaki
    upload_2019-6-28_5-0-28.png
    That 302 SBC motor would have made our 2nd 1940 Ford Sedan Delivery move quite rapidly. It would have made the stock 327 in the Sedan Delivery tame by comparison.


    “The Z/28 performance package was designed (with further modifications) to compete in the SCCA Trans-Am Series. It included a solid-lifter 302 cu in (4.9 L) V8, 4-speed transmission, power disc brakes, and two wide "skunk" stripes down the hood and trunk lid.”

    “The Z/28 option code was introduced in December 1966 for the 1967 model year. It was the brainchild of Vince Piggins, who conceived offering "virtually race-ready" Camaros for sale [11] from any Chevrolet dealer. This option package was not mentioned in any sales literature, so it was unknown to most buyers. The Z/28 option required front disc power brakes and a Muncie 4-speed manual close-ratio transmission (posi-traction was optional).”

    “It featured a 302 cu in (4.9 L) V-8, 3 in(76.2 mm) stroke crankshaft with 4 in (101.6 mm) bore, an aluminum intake manifold, and a 4 barrel vacuum secondary Holley carburetor of 780 cfm. The engine was designed specifically to race in the Trans Am series (which required engines smaller than 305 cu in (5.0 L)). Advertised power of this engine was listed at 290 hp (216 kW). This is an under-rated figure. Chevrolet wanted to keep the horsepower rating at less than 1 hp per cubic inch, for various reasons (e.g. insurance and racing classes).”


    “The factory rating of 290 hp occurred at 5300 rpm, while actual peak for the high-revving 302 was closer to 360 hp (268 kW) (with the single four barrel carb) and 400 hp (298 kW) (with optional dual-four barrel carbs) at 6800-7000 rpm. The Z/28 also came with upgraded suspension, racing stripes on the hood and trunk lid, '302' front fender emblems on the 67 and early 68 cars, and 'Z/28' emblems in late 68 & 69. “

    ASIDE:
    In the following year, 1969, my wife's brother rolled up with a green S/S model with a big 396. It was loud and fast. After a few hair raising, speed shifting runs down Coast Highway, I was happy, but in fear for this younger guy and this fast car. Luckily, he sold it when he got drafted. He is still alive, as are we, today...ha!

    In comparison between the two different green Camaros, the z-28 vs the 396 SS model, the z 28 was faster and more powerful in the long run down the straight away.
     
    Last edited: Jun 28, 2019
    catdad49 and 46poncho like this.
  3. The DZ302 cars for 1967-1969 were legendary, high-revving animals. 327 block with 283 crank resulted in the 302 ci and kept it under the 305ci limit for Trans-Am racing.
     
  4. bschwoeble
    Joined: Oct 20, 2008
    Posts: 358

    bschwoeble
    Member

    I too remember the "283" being bored to a "301" not a "302". All of this type of history will be lost, after our generation is gone.
     
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  5. Deuces
    Joined: Nov 3, 2009
    Posts: 17,213

    Deuces
    Member
    from Michigan

    '67 small journal crank= 2- bolt main...
    '68 large journal crank= 2-bolt main.....
    '69 large journal crank= 4-bolt main....
    Take a head off and check the distance of the piston at bottom dead center and bore diameter with a 6" scale.... That should give you an idea of what you have....
     
    saltracer219, bowie, lumpy 63 and 2 others like this.
  6. Deuces
    Joined: Nov 3, 2009
    Posts: 17,213

    Deuces
    Member
    from Michigan

    Actual displacement is..... 301.59 cubic inches....
     
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  7. lumpy 63
    Joined: Aug 2, 2010
    Posts: 800

    lumpy 63
    ALLIANCE MEMBER

    68 blocks were stamped MO
     
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  8. 46poncho
    Joined: May 24, 2009
    Posts: 148

    46poncho
    Member
    from Indiana

    The one my friend has is stamped d's but is a 2 bolt main

    Sent from my SM-S327VL using The H.A.M.B. mobile app
     
  9. 46poncho
    Joined: May 24, 2009
    Posts: 148

    46poncho
    Member
    from Indiana

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  10. khead47
    Joined: Mar 29, 2010
    Posts: 1,528

    khead47
    Member

    I owned a 1967 back in 1969. Funnest car I have owned !
     
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  11. lumpy 63
    Joined: Aug 2, 2010
    Posts: 800

    lumpy 63
    ALLIANCE MEMBER

    Yep all 67-68s were 2 bolt main...never seen or heard of a 68 stamped DZ. But I suppose anythings possible...
     
  12. lumpy 63
    Joined: Aug 2, 2010
    Posts: 800

    lumpy 63
    ALLIANCE MEMBER

    Jerry Mcniesh has written some great books on early Zs has all the numbers and is a wealth of info on 302s:cool:
     
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  13. 46poncho
    Joined: May 24, 2009
    Posts: 148

    46poncho
    Member
    from Indiana

    That is what I am trying to find out

    Sent from my SM-S327VL using The H.A.M.B. mobile app
     
  14. butch27
    Joined: Dec 10, 2004
    Posts: 2,786

    butch27
    Member

    Used to run one in our Formula A car..
     
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  15. ROADSTER1927
    Joined: Feb 14, 2009
    Posts: 2,528

    ROADSTER1927
    Member

    I have a 67 and it is an MO 2 bolt main and serious fun!:):)
     
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  16. Could have been restamped after a block surfacing to counterfeit a real 302.
     
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  17. squirrel
    Joined: Sep 23, 2004
    Posts: 42,657

    squirrel
    Member

    post a picture of the stamp, we'll get an idea of what it might be.

    But taking it all apart will also help you figure it out
     
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  18. Taboo56Chevy
    Joined: May 21, 2018
    Posts: 383

    Taboo56Chevy
    Member

    Sounds like a restamp and its more common than you think as a real DZ 4 bolt main block is worth a couple grand all by itself. Chevy never built a 2 bolt main 302 WITH DZ on the pad. The 67 and 68 blocks were MO blocks. The 67 blocks still had a draft tube out the back while 68's did not. I am not sure with the 67 302's but the other small blocks were small journal's and then 68 was the change over to large journals. The casting number on the rear of the block doesnt help either as it was the same for 302's 327's and 350's
     
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  19. Deuces
    Joined: Nov 3, 2009
    Posts: 17,213

    Deuces
    Member
    from Michigan

    Anybody with a stamp set can stamp a block with anything they want.... Could be a scam... :(
     
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  20. 46poncho
    Joined: May 24, 2009
    Posts: 148

    46poncho
    Member
    from Indiana

    So that is the big auestion, how does one tell if it is real???

    Sent from my SM-S327VL using The H.A.M.B. mobile app
     
  21. Deuces
    Joined: Nov 3, 2009
    Posts: 17,213

    Deuces
    Member
    from Michigan

    Drop the oil pan and check the crank to see if it's forged steel or cast iron.... I think the '69 302 crank has a #1173?:confused: Forged into it.....
    I could be wrong... :oops:
     
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  22. Ericnova72
    Joined: May 1, 2007
    Posts: 128

    Ericnova72
    Member

    1969 was primarily just DZ code, but there have been some documented late year production '68 Z28's that got a DZ coded block....but it still was 4-bolt main, DZ code were all 4-bolt main

    '67-68 were MO code, and 2-bolt main.

    2-bolt main and DZ code sounds like a scam. Need to post pics of the pad stamping so we can see the lettering type/style and size. Should also be a longer string than just "1031DZ", there is a letter missing from the front of the string.
     
  23. Taboo56Chevy
    Joined: May 21, 2018
    Posts: 383

    Taboo56Chevy
    Member

    there are ways, common mistakes are wrong font or odd spacing or wrong placement on the pad. Best thing is to take pics and talk to the Camaro restorers group. They see so many stampings, they can easily tell a real from a fake.
     
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  24. 46poncho
    Joined: May 24, 2009
    Posts: 148

    46poncho
    Member
    from Indiana

    So is there one camaro group that would be best?

    Sent from my SM-S327VL using The H.A.M.B. mobile app
     
  25. Taboo56Chevy
    Joined: May 21, 2018
    Posts: 383

    Taboo56Chevy
    Member

    The Camaro Research Group - http://camaros.org/

    They are the main group on originality and research. They also have extensive databases on Camaro's that have been authenticated and ones for know fakes.
     
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  26. Deuces
    Joined: Nov 3, 2009
    Posts: 17,213

    Deuces
    Member
    from Michigan

    That's a great website!!!!!.... ;)
     
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  27. 46poncho
    Joined: May 24, 2009
    Posts: 148

    46poncho
    Member
    from Indiana

  28. Taboo56Chevy
    Joined: May 21, 2018
    Posts: 383

    Taboo56Chevy
    Member

    Looking at that stamp, to me, that is a total fake stamping. The D and V looks wrong and the 1 after the V is totally wrong, I have only seen 0 or "I" on confirmed pads

    Here is a forum on TeamCamaro ( one of the leading forums for original Camaro's) on real DZ stamps. https://www.camaros.net/forums/15-tag-team/318642-legit-302-engine-stamping.html
     
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  29. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 22,371

    Jalopy Joker
    Member

  30. Fordors
    Joined: Sep 22, 2016
    Posts: 1,906

    Fordors
    Member

    The waffle pattern on that piston gives it away as a cast aluminum piston, not a forging as was used in all Z28 engines.
    Also the pan is not correct, at least in my experience. A Z28 pan has a short baffle that projects up from the sump at an angle to prevent oil slosh on hard braking. It will also have long sheet metal rails that interface with the baffle on the main cap bolts. I’m pretty certain your pan might not clear those main bolts with the integral studs for the baffle without some careful massaging.
    Somehow the DZ characters look like they were done using a “0” and an “I” for the D and a “7” with a tail added , maybe from a partial “0”. That’s what I see, but I am no expert at GM stampings.
     
    lumpy 63 likes this.

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