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Technical Small Block Head Mystery

Discussion in 'The Hokey Ass Message Board' started by 9sectruck, Apr 10, 2018.

  1. 9sectruck
    Joined: Dec 2, 2012
    Posts: 364

    9sectruck
    Member

    I was looking for a pair of heads for a traditional 327 build and came across these, but the casting numbers dont seem to exist 9327185!
    I know 3927185 is a chevy casting number for a 327, how is it possible to have the first 2 numbers in the wrong order.
    I can't seem to find this shape casting mark that is on the front either!
    They look like 1.94/1.5 valves too.
    Any help much appreciated. GM1.jpg GM4.jpg GM3.jpg GM2.jpg
     
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  2. Boneyard51
    Joined: Dec 10, 2017
    Posts: 6,442

    Boneyard51
    Member

    I believe those casting number where place on the mold by a human being, that being said, it is possible he/she transposed the numbers. Just my opinion, Bones
     
  3. rjones35
    Joined: May 12, 2008
    Posts: 865

    rjones35
    Member

    page 145 - http://studylib.net/doc/18242863/cylinder-head-and-block-manual-april-2006
    CHEVROLET, EARLY STYLE SMALL MAINS
    GM
    5.4
    L
    327
    68-69
    Intake Hgt:
    Exhaust Hgt:
    1.9700-2.0000" (50.038-50.8 MM)
    1.9700-2.0000" (50.038-50.8 MM)
    Casting Numbers:
    Head #:299, 3297185, 3770126, 3827185, 3911011, 3911032, 3912291, 3912313, 3917290, 3917292,
    3917293, 3923441, 3927185, 3927186, 3927188, 3928455, 3928494, 3928495, 3931637, 3931638,
    3932441, 3932454, 3946813, 3947041, 3951598, 3970126, 3973370, 3973414, 3986388, 3991492,
    3998991, 458642, 4672, 9327185
    Block #: 3794460, 3914660, 3914678, 3932368, 3932373, 3932386, 3932388, 3933180, 3955618,
    3956618, 3970014, 3970020
    Notes:
    CHEVROLET, LATE STYLE LARGE MAINS
    GM
    5.4
    O
    330
    64-67
    Intake Hgt:
    Exhaust Hgt:
    1.8600-1.8900" (47.244-48.006 MM)
    1.8600-1.8900" (47.244-48.006 MM)
    Casting Numbers:
    Head #:381918, 383821, 385101, 389394, 394189, 394497, 397497, 397742
    Block #: 381917, 381917A, 381919, 394417, 3944173
    Notes:
    OLDSMOBILE
    145
     
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  4. F-ONE
    Joined: Mar 27, 2008
    Posts: 3,271

    F-ONE
    Member
    from Alabama


  5. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    56sedandelivery
    Member Emeritus

    What are the date codes? I am Butch/56sedandelivery.
     
  6. 9sectruck
    Joined: Dec 2, 2012
    Posts: 364

    9sectruck
    Member

    Looks like F249 June 24 '69 maybe?

    Sent from my SM-T550 using The H.A.M.B. mobile app
     
  7. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 12,602

    Johnny Gee
    Member
    from Downey, Ca

    Canadian casting # is one possibility. I see your from an out of country but way further than my offering.
     
  8. rjones35
    Joined: May 12, 2008
    Posts: 865

    rjones35
    Member

    should be 68-69 327 according to the chart, seems right on.
     
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  9. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    56sedandelivery
    Member Emeritus

    I'm wondering if they could be an OTC replacement type head, hence no production casting number in the listings? Just a thought. But, as long as the chambers are what you need, the valve sizes are what you need, and the port sizes are up to the job, then it really does't make any difference what they are really. Heck, make your own story for the car shows about being, "experimental and limited run, Corvette heads". Why now, everyone else does.
    I am Butch/56sedandelivery.
     
  10. 9sectruck
    Joined: Dec 2, 2012
    Posts: 364

    9sectruck
    Member

    Good points Butch, will go and check them out for cracks etc. at the weekend.
    Still a bit of a mystery though, screw in studs and pushrod guide plates, must have been messed with at some time in the last 50 years.
    Will report back but in the meantime someone on here may have some info.

    Sent from my SM-T550 using The H.A.M.B. mobile app
     
  11. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Uhhhhh.......it seems the information in post #3 shows the ‘mystery’ casting number 9327185.....very last number in the paragraph “casting numbers - head”

    Ray
     
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  12. 9sectruck
    Joined: Dec 2, 2012
    Posts: 364

    9sectruck
    Member

    Doh! Well I'll be..........didn't spot it. Thanks.
    The HAMB is a great source of information.
    At least now I know they're not some oddball head but not as good as I'd hoped......oh well.
     
  13. Super secret Smokey Yunick head.
     
  14. Ericnova72
    Joined: May 1, 2007
    Posts: 595

    Ericnova72
    Member
    from Michigan

    They have also been cut for larger diameter valvesprings, and the valveguides have been cut for a PC style positive seal..
    Exhaust valves appear to be stainless also.

    If I had to guess I would suspect a circle track racer had them before, lot of claimer and entry level classes mandate that type of open chamber casting, supposedly to keep costs down and playing field level by not allowing real performance heads to be used.
     
  15. 9sectruck
    Joined: Dec 2, 2012
    Posts: 364

    9sectruck
    Member

    Yeah noticed that so obviously worked on at some point.

    Sent from my SM-T550 using The H.A.M.B. mobile app
     
  16. [​IMG]
    Common casting marks. I hate to say it but being mildly dyslexic I can see the numbers bieng transposed as an easy thing to do. Anyway your casting marks may be found here.
     
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  17. indyjps
    Joined: Feb 21, 2007
    Posts: 5,377

    indyjps
    Member

    Good point, early 90's there was a local guy building class specific claimer engines who would buy up 882 smogger castings. Add 2.02s etc. There should be a lot of those running around in circle track heavy areas. I sold him at least 15 sets.
     
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  18. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 12,602

    Johnny Gee
    Member
    from Downey, Ca

    To both. Numbers run together for me as well. Also one can not give me a phone number to write down quickly. I looked and looked and missed it. :oops: There's also trust to what was said that plays in as well. "OP researched casting numbers so well he has to know what he's talking about." I'm wrong again.o_O
     
  19. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Similar for me.....I MUST write down a phone number immediately ....I can't accurately remember it long enough to dial it correctly......sad but true :(

    Ray
     
  20. The joke for me I that I am supposed to be a math wiz (or so I have been told). I have to double check anything that I have read or written down. Somehow when the numbers leave my head for a piece of paper or a spread sheet they sometimes get jumbled.

    Lot of people this way, many, many who just think they are dumb and never find out why.
     
  21. 9sectruck
    Joined: Dec 2, 2012
    Posts: 364

    9sectruck
    Member

    Picking the heads up on Friday, it will be interesting to see how far from stock they are.
    Should be fine for my build whatever and better than the old heads that came on the motor.

    Sent from my SM-T550 using The H.A.M.B. mobile app
     
  22. 9sectruck
    Joined: Dec 2, 2012
    Posts: 364

    9sectruck
    Member

    Update on the heads, just got back from my road trip.
    Heads are better than expected, date matched pair and the other head bizarrely had the correct casting number 3927185.
    They have 1.94/1.5 valves fitted, machined for larger valve springs and have been nicely ported, just need a good vapour blasting to remove the surface rust and a light skim to check for flatness.
    Guy I got them from bought them at a swap meet years ago and never used them, just wish I knew the history of them.
    Thanks for all the help.

    Sent from my SM-T550 using The H.A.M.B. mobile app
     
  23. Hnstray
    Joined: Aug 23, 2009
    Posts: 12,355

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Perhaps the theory that the casting number template was transposed during a production run of heads has merit. Someone mentioned that in an earlier post. Rather than scrap them, just add the number to the records. I don't know any more than anyone else about this, just speculating....

    Ray
     
  24. HK1837
    Joined: Oct 3, 2016
    Posts: 12

    HK1837

    Despite the first digits switcheroo, these are actually 1969 307/200, 327/210 or 327/235 heads. They are 69cc, 1.72/1.5 valve and 142cc intake ports. They are the 1969 model year (accessory holes) version of the 1968 McKinnon 3911032 and Tonawanda 3917290 heads. These 3927185 heads are Saginaw cast by the looks (no T on them) but the cast marks appear to be rough cast not machined so they may be machined by Tonawanda or McKinnon rather than Flint. Remember weird stuff was happening in 1969 with big changes to the Company structure where for example engine plants were bought into their own division rather than being part of the location, plus the big strikes that saw changes in how things were built and where they were built. In original forms these are 8.75:1 on the 307 and 9:1 on the 327. Flint had the big brother 3927186 heads at this time (starting on 350/300), plus at least McKinnon were using 3927188 heads which are the same as the 3927185 heads but with 75cc chambers.
    The date code may give you more clues, the 327/210 was gone by 1969 calendar year so if the cast year has a 9 in it they have to be 307/200 or 327/235 heads.
     
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  25. Deuces
    Joined: Nov 3, 2009
    Posts: 23,753

    Deuces

    327/235..... ;)
     
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  26. HK1837
    Joined: Oct 3, 2016
    Posts: 12

    HK1837

    Yep. Standard engine on 1969 Impala. It is the same engine as the Camaro's 327/210 (which used the 307's 2BBL carb and intake) but with the 1969 L65 350's bigger 2BBL carb and intake (the L65 was simply the LM1 with a large 2BBL carb).
     
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  27. henryj1951
    Joined: Sep 23, 2012
    Posts: 2,306

    henryj1951
    Member
    from USA

  28. unfinished
    Joined: Jan 8, 2020
    Posts: 119

    unfinished
    Member

    I realize I am posting to a two year old thread, but I just now took the valve cover off a sbc that’s been stashed in the corner. The drivers side cylinder head has the strange number 9327185. The other side begins with 39.
     

    Attached Files:

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  29. Deuces
    Joined: Nov 3, 2009
    Posts: 23,753

    Deuces

    Here's a bigger picture..... 1EAE8BE9-18AA-4AF1-8F0B-58892C4D0994.jpeg
     
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