352 Head issues

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Jan 6, 2022 | 08:22 PM

bjmayberry2

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From: Wentzville, MO

352 Head issues

I usually hang out in the 48-56 F-100 forum but my SIL is rebuilding his 67 F100's 352. The Machine shop found a very small crack next to a intake valve seat. They think it will be OK but I'd sorta like to hear from you guys. Unfortunately I'm relaying this 2nd hand so I'm kinda at a loss for more specifics. I'm kinda leaning toward looking for a different head.
Your thoughts???

Jan 20, 2022 | 08:31 PM

DirtyFerd

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From: C-town,MD

I had a set of C5? heads. Not exactly sure on the part number. They had what looked like a crack between the intake and exhaust valve. Turns out it was just in the casting and they ran fine. Since your info is second hand, maybe that's what it is and that's why they feel it's okay.

Jan 21, 2022 | 10:24 AM

bjmayberry2

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From: Wentzville, MO

Ive got the head now and there appears to be a crack between the intake & exhaust seat. How did you determine it was NOT a real crack on yours?

Jan 23, 2022 | 07:51 PM

DirtyFerd

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From: C-town,MD

It was a long time ago, but I think we just looked at it with a magnifying glass. I have the heads off and next time I get a chance I''ll see if I can get a pic

Jan 23, 2022 | 07:56 PM

bjmayberry2

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From: Wentzville, MO

Thanks, I'd appreciate it, when you've got the time.

Feb 7, 2022 | 08:34 PM

DirtyFerd

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From: C-town,MD

Sorry it took so long to get back with the pics

Feb 7, 2022 | 08:38 PM

bjmayberry2

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From: Wentzville, MO

That's exactly how my SILs looks!

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Feb 10, 2022 | 11:01 AM

mark a.

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I would have psi checked it to be sure. With my luck it would have washed the cylinder down.

Feb 13, 2022 | 12:34 PM

#10

F350 1990

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From: Mooresville, NC

That crack is not significant and very common, but it WILL definitely get worse with add'l heat / unleaded fuel. You can (patch) braze it but that really doesn't address the underlying problem (unleaded fuel).

The fix is hardened seats on the exhaust side and new valves---- plenty of machine shops will drill the counterbore, punch in new hardened seats to deal with modern fuels. This approach is THE permanent long term fix.