Is there a grade on head bolts? a friend said he was going to change out his head bolts for grade 8 . Never thought about it , so what are standard head bolts?

I never really looked at them.The newer cars I know most are stretch to yield so I think they would be less than on the old cars.I know the ARPs are rated high.Rocky

I think they are grade 8. I used grade 9 bolts from Spaenaur for years with hardened washers for years with no problems.
But ARP sells head bolts fro all the head combos reasonable
http://chucker54.stores.yahoo.net/headstudbolw.html
or
http://www.summitracing.com/search/Part-...word=head+bolts

Never heard of grade 9, I've always used arp head bolts and studs, never heard what they were rated at. Anyone know?

http://www.amazon.com/Grade-Yellow-Chromate-Alloy-Length/dp/B001377Z3O

http://www.vancouverbolt.com/store/43CHCS9.HTML

http://www.fastenersdiscounts.co.cc/revi...B00137DUQ0.html

I only did it cause back in the day wanted new head bolts and spaenaur was right hear so i took the stock grade eight bolts in and said I want the same or better and that is what they sold me!

There is a world of poor quality and counterfeit hardware out there. I don't claim to know all the ins and outs, but I suggest you stick with OEM hardware, of a reputable company like ARP. I had a very difficult time controling the quality of the hardware used in my shop. I finally would not accept anything that wasn't made in the US -( had to have LE ( Lake Erie )stamped on it and was at least grade 8 ( six hash marks ). This included grade markings on the nuts and washers also. It was overkill in some applications, but at least I knew what I had. We are all familiar with grade 5 and 8 which are the most commonly used strengths in the fastener market. Then a lot of fastener companys started marketing fasteners they claimed ( and maybe true ?? ) were a step above with grade 6, 7, 9 etc ( looking for that market nitch ). They all looked pretty in the box, but you needed a college degree to decipher the different head markings on them or where they were manufactured. Upon closer examination, you could see that they weren't all made the same ( even though they might have all had the same number of hash marks on them ). Some threads looked cut, while some were rolled. Fillets under the heads were of different size - radius, as were the mating surfaces and shanks. It was pretty plain that the hardware supplier ( reputable suppliers such as Bowman, Kar products, etc )was shopping for the best price, and quality was not their major concern. Not and issue if you are bolting a license plate bracket on. Different story of you are attaching suspension or other critical parts together. Again, IMO, if you are working in a critical area on your car, you need to know that the hardware you are using aint the weak link. Hope a hardware expert will chime in on this thread.

I always use the SAE standards which is Society of
Automotive Engineers which is what we use in the auto
world
http://www.americanfastener.com/technical/grade_markings_steel.asp
I always thought the head bolts were grade 8 back when
it was a straight torque(not the torque to 70* and add
a 1/4 turn)the yield method

When I worked in the aerospace industry I bought bowman fasteners for all the special projects, they at that time sold top of the line products, that was thirteen years ago. Thanks for the info guy's I will pass it on.