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BB Mark IV coolant holes

 
Old 05-13-2019, 03:06 PM
  #1  
Fredrik71
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Default BB Mark IV coolant holes

Any opinions about drilling the two missing coolant holes on the early Mark IV block? I have stock cast iron heads and a set of FelPro 1027 head gaskets.


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Old 05-14-2019, 06:30 PM
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derekderek
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what block and heads do you have?
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Old 05-15-2019, 06:38 AM
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Fredrik71
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427 Mark IV block from 69, stock cast iron heads from 69.
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Old 05-15-2019, 08:40 AM
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derekderek
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Then ignore the page you posted about gen 5-6 stuff.
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Old 05-16-2019, 12:07 AM
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suprspooky
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I respectfully disagree with Derek, I think you could drill the small holes as suggested by Felpro if you want to (parallel cooling I think). I wish I would have seen this when I did my rebuild, my 68 just has the #3 holes. Mine works but more uniform flow is better and obviously and Dart Merlins have the holes as an example.

Experts educate us please.
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Old 05-16-2019, 07:32 AM
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derekderek
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I didn't read that completely. I thought you wanted to drill out the holes in front. My 78 block has all 3 holes between and below the cylinders. Most head gaskets have a small hole there. Be conservative. Small holes, not 1 inchers...
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