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BigBlocksRule · 01-12-2011, 08:08 AM

Most that use hardblock just fill 'em to the water pump holes. They can actually run on the street when filled, the bottom part of the bore doesn't get nearly as hot as the top, so they make sure to leave the top of the block's cooling jackets open for coolant flow.
That said, I wouldn't mess with trying to run a filled 400 on the street, with no coolant flow between the tops of the cylinders, I'd bet it'll overheat and maybe crack.

01-12-2011, 08:08 AM	#14
BigBlocksRule Registered User Join Date: Jun 2008 Location: Lubbock, TX Posts: 2,047	Re: 400 sbc price Most that use hardblock just fill 'em to the water pump holes. They can actually run on the street when filled, the bottom part of the bore doesn't get nearly as hot as the top, so they make sure to leave the top of the block's cooling jackets open for coolant flow. That said, I wouldn't mess with trying to run a filled 400 on the street, with no coolant flow between the tops of the cylinders, I'd bet it'll overheat and maybe crack.