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As I recall, the torque spec for an SBC headbolt is for the head to be dry.

Lubricating the head of any bolt will drastically increase the bolt tension for a given torque, leading to this kind of thing.

Now that it's pulled... well, I'd take it to the machine shop and see what they can do. I've never had good luck putting in my own helicoils
 

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I think you want to use a Timesert.
You can buy a kit that includes the tool and drill and do it yourself.
Hilicoils are not the best option
 

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If it’s an arp bolt it would have had a torque value with it using arp assembly lube. It’s not uncommon to pull threads out of a stock block that has had some corrosion in the water jackets. A simple helicoil CAN work but that’s old school tech and there are newer technology to use.
 

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Ya, my machine shop said to use time-sert. Bought a kit for $120. Otherwise i would have to pack up my motor and take it to the machine shop. Hope i drill it straight! Any experience with time-sert???
Yes, I've done a few but mostly spark plug holes. You only have one shot to get the hole straight. I would ask your machine shop if they have a fixture you could borrow to align the drill perpendicular to the deck.
OEM, non-Bowtie blocks can have pretty thin decks, especially after decking. Be real careful going forward. Chase all the holes with a tap before reassembly so the head bolts thread in easily.
 

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As I recall, the torque spec for an SBC headbolt is for the head to be dry.

Lubricating the head of any bolt will drastically increase the bolt tension for a given torque, leading to this kind of thing.

Now that it's pulled... well, I'd take it to the machine shop and see what they can do. I've never had good luck putting in my own helicoils
Yes, ARP usually suggests modified torque specs you have to follow rather than the stock torque spec's. Otherwise you will strip threads or stretch bolts.
 

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ya, torque value showed 70lbs on arp site. im good there on the specs. you guys make a jig or should i just go for it? one bolt needed only too, sucks.
No jig needed since the hole is already there it will follow. You can turn the block upside down on the stand and drill if wanted/needed.
 

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I’ve timesert’d a bunch of Cadillac northstar blocks and other aluminum blocks. Pretty straight forward process. Just take your time and be sure to clean up all the shavings.
 

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Tip: Grease on the tap can trap most of the shavings.
 

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Just make sure there's no shavings ending up in the piston/ring land area. You can tape this off. Grease on the drill or tap makes sense but a few chips in the water jacket isn't going to be the end of the world.
 

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Discussion Starter #18
I’ve timesert’d a bunch of Cadillac northstar blocks and other aluminum blocks. Pretty straight forward process. Just take your time and be sure to clean up all the shavings.
got the Time-sert kit. This was a vary straight forward operation. Hope it holds. The kit comes with 5 inserts and im sure ill be using them someday.
thanks for the info!
 

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I've never seen the Timesert. Can you post a few pics? I've used helicoils in the past for head bolts and never had an issue, but if timeserts are simpler/more reliable, sounds like the way to go.
Thanks!
 

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Tape a strong magnet to the drill bit shank and have someone on hand with a vac while drilling, good luck!
 
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