Hey guys, long hiatus but I'm back in a bigger better shed!

Currently cleaning amd prepping a 1275 block. Im looking to counterbore the holes on the block but i want to know what size drill bits i need for the job. I have a drill press for it and plenty of bits.

So, what size for the; head studs, the sides of the block and lastly the mains? Also with the mains is it counter boring the threads for the bolts or tue hole for the dowels??

Any help would be great! Cheers!

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http://www.ausmini.com/forums/viewtopic.php?f=3&t=93352

If I'm carrying on like a pork-chop, I'm having a great time.

If I go very quiet there's a very good chance I broke something.

Might help. viewtopic.php?f=25&t=67980

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Yeah im all over that but it didn't quite answer the questions i have. Hoping for some specifics!

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http://www.ausmini.com/forums/viewtopic.php?f=3&t=93352

If I'm carrying on like a pork-chop, I'm having a great time.

If I go very quiet there's a very good chance I broke something.

MED had a few videos on block prep
https://youtu.be/hsZmM8Xu1Ro

https://youtu.be/iWpc4njucnU

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Do you mean that you want to 'counter sink' the threaded holes in the block?
Old threaded holes like head stud holes tapped into soft cast iron like the cylinder block will sometimes have pulled the top thread of the hole up enough to sit above the deck of the block, which could interfere with the seating of a new gasket.
To remove the protruding thread, you use a 'countersink bit'. They are available at any tool shop in different diameters to suit the size of the hole. They come in different angles too, but 90 degrees is common.
You can also get away with using a larger sized drill bit to chamfer the top of the threaded hole.

"Counterbore" produces a larger diameter hole with a square bottom, which probably isn't what you need.

Yes I've been watching these as well. They also kind of gloss some of the detail im hoping to get.

I understand what a countersink does and it's difference to what a drill bit will do. Nothing of my searches gives me images of what people describe or specific bit sizes.

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http://www.ausmini.com/forums/viewtopic.php?f=3&t=93352

If I'm carrying on like a pork-chop, I'm having a great time.

If I go very quiet there's a very good chance I broke something.

3/8", same size as the thread

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