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6272990 Heads

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  • Patrick C.
    Infrequent User
    • May 25, 2022
    • 11

    6272990 Heads

    So I just picked up a pair of these 6272990 heads. They have 2.25/1.88 valves and are complete and rebuilt. My question is concerning the date code. My understanding is that the 1970's date codes were six digits. Mine are 5 digit. E238. Is this normal? Other posts say these heads weren't available 'til the 70's.
  • Joe L.
    Beyond Control Poster
    • February 1, 1988
    • 43211

    #2
    Re: 6272990 Heads

    Originally posted by Patrick Cowles (69287)
    So I just picked up a pair of these 6272990 heads. They have 2.25/1.88 valves and are complete and rebuilt. My question is concerning the date code. My understanding is that the 1970's date codes were six digits. Mine are 5 digit. E238. Is this normal? Other posts say these heads weren't available 'til the 70's.
    Patrick-------

    The GM casting 6272990 cylinder heads were never used in any PRODUCTION application that I am aware of and were certainly never originally used for any Corvette application. They are a cast iron, open chamber design and were a SERVICE-only part. They actually have 2.19" intake valves and 1.88" exhaust valves. They were introduced in the 1970's. They were intended for SHP/HD applications and are roughly a cast iron equivalent to 1969+ SHP/HD aluminum cylinder heads. They were once available under GM PART #6260482 but have been discontinued for quite some time now.

    The 2 digit year casting date was pretty much a "phenomenon" of the old Tonawanda cast iron foundry. By the time these heads were manufactured I believe that big block cast iron castings had been transferred to the Defiance, OH foundry which usually used a 1 digit year. So, these heads were likely cast in 1985 or 1995. Inasmuch as these heads were never used in PRODUCTION, the casting date really is of little significance.
    In Appreciation of John Hinckley

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