Head bolts vs head studs

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Jan 19, 2017 | 01:01 PM

Greatwhite94

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Head bolts vs head studs

(1994 f250 7.3 idi na 4x4) so i eventually wanna install a turbo and maybe eventually upgrade my engine to all stage 1 performance. But my question is what is the real difference between head bolts and head studs, i dont really know the difference between them but what i do know is i find head bolts from 30 to 100 but i cant find head studs for anywhere under 400. But i just wanna know the true difference.

Jan 19, 2017 | 01:11 PM

hairyboxnoogle

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about 60,000 psi of clamping load.

Jan 19, 2017 | 09:59 PM

DarkOverCast

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Basically if you want to run above 12psi safely then you want head studs, although some users here have pushed close to 20, it's not exactly safe. Other than that they don't really have many benefits

Jan 19, 2017 | 11:09 PM

hairyboxnoogle

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Quote:

Originally Posted by DarkOverCast

Basically if you want to run above 12psi safely then you want head studs, although some users here have pushed close to 20, it's not exactly safe. Other than that they don't really have many benefits

On a 7.3 15-20 is fine on bolts. Its the 6.9 you dont want to go over 10-12

Jan 21, 2017 | 12:27 AM

Ford_Six

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From: The Big, Oregon

The material is different, allowing a higher torque and therefore a tighter clamping force that is more resistant to stretch and loss of clamping force.

Jan 21, 2017 | 02:45 PM

hairyboxnoogle

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Quote:

Originally Posted by Ford_Six

The material is different, allowing a higher torque and therefore a tighter clamping force that is more resistant to stretch and loss of clamping force.

That is right, but not all of it. Bolts will twist and deform before a stud will, regardless of material. Also, bolts are coarse (in this case) and the top of the stud is fine thread, allowing more clamp load per ft./lb of torque applied, so again, you get more clamping, without distortion from twisting. Factory torque spec is 90lbs on 7.3 iirc, at 100lbs they stretch, to be sure, check out the "IDI headstud tech" thread via search on here. Should answer any and all of your questions.