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496 Heads

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Old 07-14-2019, 10:43 AM
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Default 496 Heads

Hi, following some valve guide issues last year I bought 2 good used cylinder heads for my 496 Mag Ho off eBay.
Having only just got round to fitting them some 10 months latter I have found that everything seems the same except at each end of the head where the 2 shorter (mid sized) head bolts go are not shorter on the used heads that I have bought. I cant see anything online showing a different variant of head showing all long bolts without the 2 shorter ones.

Does anyone know any more about this as I am worried that I may have incorrect heads despite everything else looking the same?

Thanks
Simon
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Old 07-14-2019, 11:03 AM
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Lay the heads side by side and take some pictures to post.
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Old 07-14-2019, 02:38 PM
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Old 07-14-2019, 02:45 PM
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Marked in red is the difference between the two heads on the end 2 bolts that would normally be the middle length head bolt. Its recessed on my old 496 heads but level with the rest on the new head.
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Old 07-14-2019, 03:34 PM
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Probably late model versus early model truck versus marine. Try the headbolt first, if its too short, just buy a longer headbolt for that hole. It will work, I've done it twice myself. Throw a set of Raylar roller rockers on there while you have it opened up.
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Old 07-14-2019, 08:40 PM
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They look like they are two different casting numbers. I can read all of the numbers on the one but if you post the two casting numbers it might help figure it out.
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Old 07-17-2019, 05:41 AM
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Thanks for the replies gents.

Keith sounds pretty conclusive so I have ordered some more bolts. Hoped I might be able to get them in the UK but its a nightmare getting 496 stuff over here, so ordered a set from Summit Racing.

Billk, I still would be interested in what you make of the casting #. I am pretty sure there was no casting numbers but I will check again later.

Cheers Simon
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Old 07-17-2019, 05:45 AM
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Have just seen what I was missing in the picture the casting numbers are on the intake ports, will post them later
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Old 07-20-2019, 04:39 PM
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Default Casting numbers




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Old 07-20-2019, 04:40 PM
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Bill if you have any info from those casting numbers it would be great.

Cheers
simon
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