I'd pay more for a good aluminum one than for an iron one.

If the castings are flawed, fix the flaw. Flawed iron castings exist also.

I've spent much of my career in casting/forging/etc. metals and plastics, there are more ways to do it wrong than right. Get the design and process right and you can have an excellent aluminum-alloy head, do it wrong and it doesn't matter if it's made of iron or nonobtainium it'll fail.

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Gone to the dark side

- Jeff