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Discussion Starter · #1 ·
This has bugged me for some years now. The head gaskets have some holes reduced down to a drill size and in some cases it is totally blocked off.
I just don't get why the head gasket maker would do this. The Vic Jr intake only has water passing through the front also.

Should I do something about this?
 

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Use the gasket as is and install correctly.
 

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The head gaskets have some holes reduced down to a drill size and in some cases it is totally blocked off.
I just don't get why the head gasket maker would do this.
It's easier and cheaper to fine-tune the coolant flow with the gasket than with additional machining of the block.
The Vic Jr intake only has water passing through the front also.
There is no purpose to a rear coolant passage, as it has no where to go in a balanced-flow setup. In other words, the coolant has no reason to flow across a rear passage (pressure differential), even if it was open. In the front it only flows part of the way across just to get to the T-stat or heater outlet.

David
 

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Ive wondered about this too. My new Edelbrock heads say to drill the block with a 1/8 bit. I probably will, but I know guys that dont and never have overheating issues.

Matt
 

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Drill it. Lacking it doesn't cause a general overheating issue, but rather a hot-spot that will cripple that one cylinder.

David
 

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I've always drilled them. You can lay the gasket over the block... and over the head... to see where they need to go. You can drill either the block or head. I like the position that is offset, and not directly above the cylinder at 12 o'clock. 289 blocks have the steam hole at 12 o'clock. Later blocks have them off to the side a bit.

I'd drill the block. No big deal. Use the head gasket as a template.

Good Luck!
 

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Discussion Starter · #7 ·
For drilling something like that you can put vaseline on the drill but and it will hold the shavings so they don't fall down into the engine. I had to drill out my oil dip stick hole in the timing cover. The chrome aftermarket dip stick was larger than the hole. Used the vaseline trick. It works.

Ok so if I understand what y'all are saying, if I have holes in the block that are not in the head or holes in the head gasket that are not in one or the other I should drill those out?
 

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For drilling something like that you can put vaseline on the drill but and it will hold the shavings so they don't fall down into the engine. I had to drill out my oil dip stick hole in the timing cover. The chrome aftermarket dip stick was larger than the hole. Used the vaseline trick. It works.

Ok so if I understand what y'all are saying, if I have holes in the block that are not in the head or holes in the head gasket that are not in one or the other I should drill those out?
The thing with steam holes on SBF's... is that they moved them. 289's had steam holes that were at 12 o'clock to the cylinder. Some 302's were at 11 o'clock, some were at 1 o'clock.

Most gaskets have holes punched at all three spots.

You just need to look at the head to see where it's drilled, then drill a matching hole in the block. You can use the head gasket as a template.

The head can be drilled to match the block as well. Some aftermarket heads have a half moon groove that sweeps across all locations to make for an 'idiot proof' install. :)

Good Luck!
 

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Usually, you're only looking for the missing hole on the head or block on #4 and #8 cylinders. Usually the block, at the 11 o'clock (cyl 4) or 1 o'clock (cyl 8) positions.

David

Here you can see the coolant hole I added on this small block's cylinder #8:
 
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