MrBiglez
Registered User
So my question is can you bore out the head stud size on a 6.9 to the 1/2 in head studs by any chance? Or someone point me in the right direction?
6.9 head stud upgrade possibility?
- Thread starter MrBiglez
- Start date
No, many threads on many forums on this.
The 6.9 stud upgrade is fine as is for almost all purposes
The 6.9 stud upgrade is fine as is for almost all purposes
icanfixall
Official GMM hand model
So far I recall a member a few years back posting about how he used a hand drill to do just that. He installed the 6.9 heads on his 7.3. I believe he said the drill bit followed the hole in the heads fine. Why are you asking this question? I have not read other forums why this is not done. I just do not red other forums. Russ knows much more than I do on these engines and I respect what he has posted about this drill out is not done. Would like to know more why its not done. Pushing bad advice or information is not what I do.
i see no reason why this cant be done if youre using 6.9 heads on a 7.3.
i personally would not do this. i would find 7.3 heads.
as Russ stated 6.9 studs on a 6.9 with 6.9 heads are just fine.
trying to use the larger studs on a 6.9 short block requires alot of drilling, and tap work, if it even works at all without reducing the integrity of the block.
in short, anything can be done. but why waste the time?
i wouldnt even use 7.3 heads on a 6.9 with the bolt shims.
just my unprofessional opinion from a pretty vague thread.
i personally would not do this. i would find 7.3 heads.
as Russ stated 6.9 studs on a 6.9 with 6.9 heads are just fine.
trying to use the larger studs on a 6.9 short block requires alot of drilling, and tap work, if it even works at all without reducing the integrity of the block.
in short, anything can be done. but why waste the time?
i wouldnt even use 7.3 heads on a 6.9 with the bolt shims.
just my unprofessional opinion from a pretty vague thread.
The way i am reading it, is he wants to drill out the 7/16 hole in the block to tap and fit the 1/2 studs. Short answer is No.....
79jasper
Chickenhawk
Someone did try it, iirc. Didn't last though. Think it was one of the Justin's.
The 6.9 actual studs will be more than enough.
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The 6.9 actual studs will be more than enough.
Sent from my SAMSUNG-SM-G890A using Tapatalk
^^^ i think there was a problem because there is not enough size difference to cleanly remove the 7/16 thread for a fresh 1/2 thread. I think it was Justin that tried it and I think you are right, I don't think it lasted. It torqued down but I think it eventually failed.
MrBiglez
Registered User
Well then thank you for the advice to even think about that. If its going to destroy the block then I'm going throw that idea away. So if the 7/16 is good then I will go with that. This is all for my future project that I'm going to have and this the best way to get valuable information. Thanks guys for answering my question.
If ya want to see the difference in threads, take a 7/16" nut and drill it out for a 1/2" thread, see what's left of the 7/16" thread root. Drill size close fit 27/64" 75% thread, loose fit 15/32" 50% thread.
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icanfixall
Official GMM hand model
OIC what has been posted here... Sometimes I do not see whats posted. I see now the original poster was asking if a 7/16 threaded bolt hole can be drilled out to 1/2 inch threaded bolt hole. Psychically it can be done but you will not have a full thread for the 1/2 bolt. So there you have it from this side of the screen. Might be better for more questions to be asked by me in the future. I kind of ran with this vague original post thinking someone wanted to use 6.9 heads on a 7.3. That can and will work from all I have read on this forum.
As for increasing the 6.9 stud that too is fine the way we buy them from ARP. Maybe drilling and tapping to a 9/16 stud would work but make a mistake and you have lost a good block. No new 6.9 or 7.3 blocks have been made in decades.
As for increasing the 6.9 stud that too is fine the way we buy them from ARP. Maybe drilling and tapping to a 9/16 stud would work but make a mistake and you have lost a good block. No new 6.9 or 7.3 blocks have been made in decades.
PwrSmoke
Full Access Member
Another thing, the top deck thickness was increased on the 7.3L block by 0.060"(nearly 5/8-in.) over the 6.9 (0.560" from .500") to support the larger bolts better and provide a stronger surface. Also, the bosses for the lower bolts in the 7.3L head were enlarged and given ribs to better support the larger bolts.
IMO, a 6.9L head with a stud kit is stronger and provided a better hold than a 7.3L factory setup.
IMO, a 6.9L head with a stud kit is stronger and provided a better hold than a 7.3L factory setup.
freebird01
Post Turtle!
i thought the issue of trying to go to a larger stud was a matter of breaking into the water jacket
jaluhn83
Full Access Member
I doubt you'd break into the water jacket, the main issue would be the small increase not being enough to clean up the thread and also the possibility of misalignment if doing it by hand. Only safe was I can think of to do it would be to oversize the hole significantly and then insert a threaded insert with the desired final hole size. This would most likely break into the water jacket though when you went to a larger hole size. Could possibly use a heli-coil, but again many chances to screw things up.
The standard ARP head studs are fine for anything realistic. I'm running 18-20 psi of boost on them with no issues though I did deck the pistons slightly. The only person I know of who has ever had issues with them in Justin, and that's because he thinks he needs to run some insane boost numbers - like 30 psi?
The standard ARP head studs are fine for anything realistic. I'm running 18-20 psi of boost on them with no issues though I did deck the pistons slightly. The only person I know of who has ever had issues with them in Justin, and that's because he thinks he needs to run some insane boost numbers - like 30 psi?
