Thread: New block
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Old 05-08-2017, 09:27 AM   #59
rotorwrench
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Join Date: Jun 2010
Location: San Antonio, Texas
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Default Re: New block

Changing the main journal structure would take a different bottom end too. I think you have the right idea. If you stray too far from the OEM it complicates things. That may have been what stumped the Motor City project.

I think the French made block's biggest improvement was the modern casting material formula. It's a hybrid of the early 239 CID 99A/59A types and the later 8BA types. My only problem with it is that it is already relieved. Not much choice there. Even SF flatheads decided to remove that big governor lump on the back too. Starting with a fresh casting would eliminate stuff like that.

The 8BA would be the easier one to cast. The half bell part of the earlier block alone makes it a more complicated project. Changing exhaust ports may complicate things too. If anything grows larger or changes shape it makes for changes to water jackets or other internal/external block dimensions. Most Folks would like to be able to go out to at least 3 3/8" without worry but if the bore size grows too much, the whole block will have to grow too. I don't think anyone wants a 337 Lincoln sized block.
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