I am replaceing the rusted out heads on my 460 F350. Do I need to use heads bolts or can I replace the exterior ones with Grade 8 bolts instead. Since I only need the exterior ones, can't see spending the $$ for a new set if I don't need to.

 

If you need to replace some of them, you need to replace all of them, and no I would not use G8 hardware store bolts.

 

That's what I was afraid of. I will order a new set today. Thanks

 

What about stronger bolts (Grade-10?) from a specialized place like Fastenal or McMaster-Carr?

 

Problem .. well use to be was Head bolts were a odd length. G10 might work but you might have a hard time finding that size in the length you need. Longer one just don't fit. Fastenal is a LOT of import stuff. McMaster - Carr is a great place but they take to much of my money every year! LOL I think you woudl still be better off just getting a set and know there the right grade and size to do the job.

Just looked Only thing McMaster has in the Grade 10.9 with the flange head is metric. That kind of sucks! I need to complain to them! LOL

 

Yea I agree and while I'm all for saving a few bucks/short cuts whenever possible, and even though they might work just fine I wouldn't use the grade 8's, replace all the bolts with "stock" head bolts.

You don't want to have to pull the head/s again because the bolts exact makeup wasn't right, might not withstand the temperature swings long term for example.

 

Class 10.9 is a metric specification, roughly equivalent in strength to SAE grade 8. That's why you can't find standard size fasteners with a class 10.9 strength rating.

As for the head bolts, I would try ARP if you don't want factory replacements. You can probably find replacements at say NAPA or CarQuest. I think if you're going to replace any of them that you should go ahead and replace them all.

 

I always get a new set of head bolts for a major overhaul or a head gasket job. Not a place to go cheap. If you want better than stock bolts, or would rather have studs then ARP should make something for you

 

It was just a random idea, nothing more, but thanks for the explanation of why it was a bad idea

I have seen metric bolts that have 12.9 written on their head, would those be roughly equivalent in strength to Grade-10 standard bolts? (this is just for my own general knowledge)

 

The first number is the tensile strength or the pressure required to actually break the bolt.. This number can be between 4 and 14 with 14 being the toughest. To convert that number into something useful, take the first number on the head, multiply it by 100 (this give you tensile strength in N/mm2), then multiply it by 145 to get you the PSI that the bolt is rated at. A metric bolt with a 12 for the first digit, for example, would have a tensile strength of 174,000 PSI (12x100=1,200N/mm2 x 145=174,000psi).

Bolt Grade Markings and Strength Chart

<table style="width: 447pt; margin-left: 3.75pt;" border="1" cellpadding="0" cellspacing="0" width="596"><tbody><tr style="height: 24pt;"> <td rowspan="2" style="width: 16%; height: 24pt; padding: 0.25pt; background: none repeat scroll 0% 0% rgb(217, 217, 217);"> Head Markings
</td> <td rowspan="2" style="width: 13%; height: 24pt; padding: 0.25pt; background: none repeat scroll 0% 0% rgb(217, 217, 217);"> Grade or Class
</td> <td rowspan="2" style="width: 15%; height: 24pt; padding: 0.25pt; background: none repeat scroll 0% 0% rgb(217, 217, 217);"> Material
</td> <td rowspan="2" style="width: 15%; height: 24pt; padding: 0.25pt; background: none repeat scroll 0% 0% rgb(217, 217, 217);"> Nominal Size Range
(Inches)
</td> <td colspan="3" style="height: 24pt; padding: 0.25pt; background: none repeat scroll 0% 0% rgb(217, 217, 217);"> Mechanical Properties
</td> </tr> <tr> <td style="width: 11%; padding: 0.25pt; background: none repeat scroll 0% 0% rgb(217, 217, 217);"> Proof Load (psi)
</td> <td style="width: 13%; padding: 0.25pt; background: none repeat scroll 0% 0% rgb(217, 217, 217);"> Minimum Yield Strength (psi)
</td> <td style="width: 13%; padding: 0.25pt; background: none repeat scroll 0% 0% rgb(217, 217, 217);"> Minimum Tensile Strength (psi)
</td> </tr> <tr> <td colspan="7" style="padding: 0.25pt; background: none repeat scroll 0% 0% rgb(217, 217, 217);"> American Bolts
</td> </tr> <tr style="height: 44.25pt;"> <td rowspan="2" style="padding: 0.25pt; height: 44.25pt;" valign="top">
No Markings
</td> <td rowspan="2" style="padding: 0.25pt; height: 44.25pt;" valign="top"> Grade 2
</td> <td rowspan="2" style="padding: 0.25pt; height: 44.25pt;" valign="top"> Low or Medium Carbon Steel
</td> <td style="padding: 0.25pt; height: 44.25pt;" valign="top"> 1/4 thru 3/4
</td> <td style="padding: 0.25pt; height: 44.25pt;" valign="top"> 55,000
</td> <td style="padding: 0.25pt; height: 44.25pt;" valign="top"> 57,000
</td> <td style="padding: 0.25pt; height: 44.25pt;" valign="top"> 74,000
</td> </tr> <tr style="height: 45pt;"> <td style="padding: 0.25pt; height: 45pt;" valign="top"> Over 3/4 thru 1-1/2
</td> <td style="padding: 0.25pt; height: 45pt;" valign="top"> 33,000
</td> <td style="padding: 0.25pt; height: 45pt;" valign="top"> 36,000
</td> <td style="padding: 0.25pt; height: 45pt;" valign="top"> 60,000
</td> </tr> <tr style="height: 45pt;"> <td rowspan="2" style="padding: 0.25pt; height: 45pt;" valign="top">
3 Radial Lines
</td> <td rowspan="2" style="padding: 0.25pt; height: 45pt;" valign="top"> Grade 5
</td> <td rowspan="2" style="padding: 0.25pt; height: 45pt;" valign="top"> Medium Carbon Steel, Quenched and Tempered
</td> <td style="padding: 0.25pt; height: 45pt;" valign="top"> 1/4 thru 1
</td> <td style="padding: 0.25pt; height: 45pt;" valign="top"> 85,000
</td> <td style="padding: 0.25pt; height: 45pt;" valign="top"> 92,000
</td> <td style="padding: 0.25pt; height: 45pt;" valign="top"> 120,000
</td> </tr> <tr style="height: 45pt;"> <td style="padding: 0.25pt; height: 45pt;" valign="top"> Over 1 thru 1-1/2
</td> <td style="padding: 0.25pt; height: 45pt;" valign="top"> 74,000
</td> <td style="padding: 0.25pt; height: 45pt;" valign="top"> 81,000
</td> <td style="padding: 0.25pt; height: 45pt;" valign="top"> 105,000
</td> </tr> <tr style="height: 1.25in;"> <td style="padding: 0.25pt; height: 1.25in;" valign="top">
6 Radial Lines
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> Grade 8
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> Medium Carbon Alloy Steel, Quenched and Tempered
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> 1/4 thru 1-1/2
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> 120,000
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> 130,000
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> 150,000
</td> </tr> <tr style="height: 44.25pt;"> <td rowspan="3" style="padding: 0.25pt; height: 44.25pt;" valign="top"> Stainless markings vary. Most stainless is non-magnetic
</td> <td rowspan="3" style="padding: 0.25pt; height: 44.25pt;" valign="top"> 18-8 Stainless
</td> <td rowspan="3" style="padding: 0.25pt; height: 44.25pt;" valign="top"> Steel alloy with 17-19% Chromium and 8-13% Nickel
</td> <td style="padding: 0.25pt; height: 44.25pt;" valign="top"> 1/4 thru 5/8
</td> <td style="padding: 0.25pt; height: 44.25pt;" valign="top">
</td> <td style="padding: 0.25pt; height: 44.25pt;" valign="top"> 40,000 Min. 80,000 – 90,000 Typical
</td> <td style="padding: 0.25pt; height: 44.25pt;" valign="top"> 100,000 – 125,000 Typical
</td> </tr> <tr style="height: 24pt;"> <td style="padding: 0.25pt; height: 24pt;" valign="top"> 3/4 thru 1
</td> <td style="padding: 0.25pt; height: 24pt;" valign="top">
</td> <td rowspan="2" style="padding: 0.25pt; height: 24pt;" valign="top"> 40,000 Min. 45,000 – 70,000 Typical
</td> <td style="padding: 0.25pt; height: 24pt;" valign="top"> 100,000 Typical
</td> </tr> <tr style="height: 30pt;"> <td style="padding: 0.25pt; height: 30pt;" valign="top"> Above 1
</td> <td style="padding: 0.25pt; height: 30pt;" valign="top">
</td> <td style="padding: 0.25pt; height: 30pt;" valign="top"> 80,000 – 90,000 Typical
</td> </tr> <tr style="height: 19.5pt;"> <td colspan="7" style="height: 19.5pt; padding: 0.25pt; background: none repeat scroll 0% 0% rgb(217, 217, 217);"> Metric Bolts
</td> </tr> <tr style="height: 1.25in;"> <td style="padding: 0.25pt; height: 1.25in;" valign="top">
8.8
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> Class 8.8
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> Medium Carbon Steel, Quenched and Tempered
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> All Sizes thru 1-1/2
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> 85,000
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> 92,000
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> 120,000
</td> </tr> <tr style="height: 1.25in;"> <td style="padding: 0.25pt; height: 1.25in;" valign="top">
10.9
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> Class 10.9
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> Alloy Steel, Quenched and Tempered
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> All Sizes thru 1-1/2
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> 120,000
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> 130,000
</td> <td style="padding: 0.25pt; height: 1.25in;" valign="top"> 150,000
</td> </tr> <tr style="height: 44.25pt;"> <td rowspan="3" style="padding: 0.25pt; height: 44.25pt;" valign="top"> Stainless markings vary. Most stainless is non-magnetic
</td> <td rowspan="3" style="padding: 0.25pt; height: 44.25pt;" valign="top"> A-2 Stainless
</td> <td rowspan="3" style="padding: 0.25pt; height: 44.25pt;" valign="top"> Steel alloy with 17-19% Chromium and 8-13% Nickel
</td> <td style="padding: 0.25pt; height: 44.25pt;" valign="top"> 1/4 thru 5/8
</td> <td style="padding: 0.25pt; height: 44.25pt;" valign="top">
</td> <td style="padding: 0.25pt; height: 44.25pt;" valign="top"> 40,000 Min. 80,000 – 90,000 Typical
</td> <td style="padding: 0.25pt; height: 44.25pt;" valign="top"> 100,000 – 125,000 Typical
</td> </tr> <tr style="height: 24pt;"> <td style="padding: 0.25pt; height: 24pt;" valign="top"> 3/4 thru 1
</td> <td style="padding: 0.25pt; height: 24pt;" valign="top">
</td> <td rowspan="2" style="padding: 0.25pt; height: 24pt;" valign="top"> 40,000 Min. 45,000 – 70,000 Typical
</td> <td style="padding: 0.25pt; height: 24pt;" valign="top"> 100,000 Typical
</td> </tr> <tr style="height: 30pt;"> <td style="padding: 0.25pt; height: 30pt;" valign="top"> Above 1
</td> <td style="padding: 0.25pt; height: 30pt;" valign="top">
</td> <td style="padding: 0.25pt; height: 30pt;" valign="top"> 80,000 – 90,000 Typical
</td> </tr> <tr style="height: 0.5in;"> <td colspan="7" style="padding: 0.25pt; height: 0.5in;" valign="top"> Tensile Strength: The maximum load in tension (pulling apart) which a material can withstand before breaking or fracturing.
Yield Strength: The maximum load at which a material exhibits a specific permanent deformation
Proof Load: An axial tensile load which the product must withstand without evidence of any permanent set.
</td></tr></tbody></table>

 

Sorry to dig up such an old thread. But this chart is so handy!

 

unless you are using ttys (torque to yeild bolts) which you aint, you can re-use a head bolt set from about any street 460.

that being said, dont pop off the bottoms and not the top, you will blow the head gasket shortly thereafter....do it right or not at all (also head bolts tend to be shouldered to minimize movement