Advise: cylinder heads 6x8 - Pontiac GTO Forum
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post #1 of 3 (permalink) Old 04-20-2012, 06:05 PM Thread Starter
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Advise: cylinder heads 6x8

The #13 heads I bought for my 400 may not be salvageable.

How much can these 6x8 heads be milled down? To the point of creating 9.5 CR, I have forged flat top pistons .030. Ive heard too that the small valves can opened up to accept large ones.

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post #2 of 3 (permalink) Old 04-27-2012, 11:00 PM
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not possible with those heads and keep your existing pistons.
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post #3 of 3 (permalink) Old 04-28-2012, 06:55 PM
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Reason? You'd have to cut more off the heads than there is metal available --- the decks would be paper thin, that is if you didn't cut through into the water passages just trying.


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