I'd use them on every stud, you want that clamp load properly distributed. No need for a washer between the nut and insert.
7.3 Heads on a 6.9
- Thread starter icanfixall
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I'd use them on every stud, you want that clamp load properly distributed. No need for a washer between the nut and insert.
shocktrooper
Registered User
Any real quality difference? The TFS set is the same price as arp but for 20 instead of 10
Ehhh... TFS isn't up front on their material, while ARP is... TFS heads can push into the mid 350-400 hp range, but our IDI engines see a ton more pressure in the cylinder...
If it were me... It's a tough call, but I'd spring for the ARPs and not do any second guessing on their quality
If it were me... It's a tough call, but I'd spring for the ARPs and not do any second guessing on their quality
shocktrooper
Registered User
I'm actually using grade 8 bolts on the lower side of the head where they made the boss longer right at the manifold. It's just hard to get a 7/16 thread with a 1/2 shank. So I orders some of those washers that will take up the space.
how long has this been running?
IMO, i would never use grade 8 on heads.
head bolts are hardened.
shocktrooper
Registered User
Have not put them on just yet need to get dowel pins. I was thinking the same thing but at 85 ft lbs. I didn't know if I was gonna need stronger. The ones that came out where grade 8. But now that you have said that I might go a little higher.
grade 8 will stretch on you, guaranteed. thats what they are designed to do.
stainless will snap.
you need hardened bolts. dont stick just anything in there.
use the correct grade bolts.
stainless will snap.
you need hardened bolts. dont stick just anything in there.
use the correct grade bolts.
I could go all structural engineer on this and calculate psi ratings for grade 8 and the awesome-sauce ARP uses, but it wouldn't be a fair comparison by a long shot!
Just please don't skimp on the head bolts/studs...
Just please don't skimp on the head bolts/studs...
OEM factory head bolts are carburized and hardened, carburization is .030 to .035 depth at 1750*F and oil quenched to harden. IIRC.
icanfixall
Official GMM hand model
Well said Brian & Mel. Grade 8 may work.. for a time but you will be redoing them later. This use of grade 8 bolts reminds me of installing ARP studs without removing the heads. Doing it one stud at a time. Scares the hell out of me but some have done it. My feelings are it can be done but how long it lasts is another thing. I know where and when it would fail on me. I'm just that lucky guy old on a black highway no moon nite and its late sunday when it lets go. Nobody can force you to do the right thing but if one has a hell bent pension to "do it" then please keep this forum informed on what happens. Thats how we all learn and change.
No I would never attempt grade 8 head bolts nor would I change to studs one bolt at a time in frame either.
No I would never attempt grade 8 head bolts nor would I change to studs one bolt at a time in frame either.
shocktrooper
Registered User
Yea I've been looking for longer 7/16 studs for those holes. Can't find any longer though. If you guys know where to find some let me know. Been on arp and everything nobody has longer than 6 inch. It requires a 7 for those 4 holes on each head.
http://www.summitracing.com/parts/arp-ap6-750-1sb/overview/
6.75" ARPs... I'd pop the head in place and take a depth measurement all the way down into the block to verify exactly how long you need, then call ARP.
6.75" ARPs... I'd pop the head in place and take a depth measurement all the way down into the block to verify exactly how long you need, then call ARP.
icanfixall
Official GMM hand model
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