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06-07-2024, 10:08 PM | #1 |
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1971 487 X Heads
Does anyone know when GM started heat treating the exhaust valve seats on their cylinder heads?
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06-08-2024, 04:44 PM | #2 |
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Location: Arkansas - In the middle of everything.
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Re: 1971 487 X Heads
1971 with the introduction of unleaded gas at the pumps.
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