781 bbc heads
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781 bbc heads

  1. #1
    Senior Member slotracer's Avatar
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    Default 781 bbc heads

    Ok, now that mortec is gone cannot find out what they are. Can someone please tell me what I have? 781 are the last 3 #'s.
    Thanks
    slot
    87 eliminator
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    new owner of the redneck yacht club
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  3. #2
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    large oval port open chamber heads with small intake valves, work well with larger valves and some bowl clean up work, lots of guys love them 468-496 low comp mills.

  4. #3
    Senior Member slotracer's Avatar
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    Thanks, do you know what size valves were stock?
    slot
    87 eliminator
    next boat ??????????????
    new owner of the redneck yacht club
    Stockton, ca.

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  6. #4
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    2.06 int x 1.72 exh and i think they have chambers in the 119-122cc range

    heavy 3/8 valves should be maybe up-graded to 5/16 with the valve up sizing to lightin things up

  7. #5
    Senior Member slotracer's Avatar
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    well, with valves that small that could be why it's not very fast. not inhaling enough.
    slot
    87 eliminator
    next boat ??????????????
    new owner of the redneck yacht club
    Stockton, ca.

  8. #6
    steelcomp was here
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    Pretty common upgrade is to install 2.19/1.88 11/32" stem valves. With a good valve job and some minimal bowl work they will flow over 300, up to about .650 lift. Good for 600hp easy and with more work and a little better flow they will go 700.
    If God is your co-pilot, change seats!
    Acts 2:38, the perfect answer to the perfect question.

  9. #7
    AKA Blownjet 468 Blowncat 509's Avatar
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    Or in other terms, you got 1 of the 2 best open chamber oval port gm castings made.. 049 being the other

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