Opened up an old 400 - what is this???

mbaird said

Yep ... I bet someone heli coiled the water neck holes whithout removing intake . Doubt they will harm anything .
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I would agree except that looks like a mighty big pile of chips to just be two water neck drill outs, and I haven't seen cast chips like that for installing two heli-coils. So IDK. But I sure am curious