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#1 |
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A question for you guys, the NHRA specks for the 426 wedge is max bore of 4.33, the standard bore on a 440 is 4.32. NHRA shows the pistons allowed for the 426 but Im wondering if I can use a 440 block and the standard bore piston with NHRA excepted numbers. I hope I explained this right. Maybe call the tech people but I have no phone number. Thanks
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#2 |
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I do not see why you could not run the 440 block but
it will be difficult to find one that would clean up at .010 over. They all have pretty worn cylinder bores that I can find any more Back in the day you could buy from Mopar Perf. an unbored 440 block that could be built at .060 over for a 426. But I have not seen one for 30 years.
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#3 |
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I have a 70 and 74 block with good cylinders so that’s not a problem. I’m thinking more about the piston numbers
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#4 |
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I don’t think it would be an issue in SS, but it’s probably a no-go in Stock as the 426W and the 440 have different compression height on the pistons. Ultimately NHRA tech would make that call.
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#5 |
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You can use the 440 block with a approved 426 piston as long as you are not .080 or more on the 426 bore and the block has the same deck height as specified for the 426 block.
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#6 |
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Just looked at both specs 426 has a 2.015 comp height .042 deck with a .020 gasket. 440 has 1.94 ch .027 deck and a .021 gasket. No 440 piston has that ch except the 6 pac but it has valve pockets, a no no. So it’d have to be a .070 over 426 piston with the right numbers on top. What a can of worms.
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#7 | |
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#8 |
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Back in the mid 70s my Max had a bad cylinder so I found an industrial block out of a 60 ton crane, it was a very strong block.
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#9 |
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MH or Industrial blocks have a water hole for spark plug cooling passages that are in the MH or industrial heads. They are easy to spot.
If you find a block try to get one that has the Dash end number(-1) closer to one or zero. The higher the dash number the more mold/casting modifications. Closer to zero or 1 is usually a block that has been cast matching the original prints. A -1 could be a lot better core than a block with a -15 on it. Sonic testing is important
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Adger Smith (Former SS) Last edited by Adger Smith; 10-01-2023 at 11:55 PM. Reason: add |
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#10 |
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I thought they only used the block castings ten
times 10 times before retiring them but that was a longtime ago.
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