I have been in contact with ARP and they have given me an M12 Stud part number: AU7700-1B.

This is 7.700" long and made from their standard stud material - however being a 12mm shank they should be able to take a lot more abuse and hold a higher torque value.

Seeing as i'm overseas and i'm trying to buy these so they are ready for when i get back, will the extra 75 thou (1.9mm) extra length make much difference?

What is the standard head stud length on the 996 turbo? anyone got one to measure? From the internet i have got 7.625" but i cannot verify it.

 

knowledgable replies to this will be few and far between. IMO, you wont have any issues with the overall length. The length of the threads that go into the case must be precise though, as the 12x1.5 thread is smaller than your shank, so if it doesn't hit the bottom of the hole, you wont be able to preload them properly and they will flare the base of the case surface as they attempt to drive themselves further in. Good luck!

 

Thanks Sean, I asked them for dimensions of the threaded lengths but got no reply. I guess I can just buy one and see how it fits in my old cases. Don't know if anyone has actually tried them before.

 

Cost compared to know good 12mm? Any material specs given?

 

been wondering this same thing. Specifically why a known length off the shelf 12mm stud from ARP wouldnt work. Interested to see what you come up with

 

The ones OP is looking at are the basic 8740 chromoly the set with washers and nuts will run about 450ish and ARP2000 will run about 650ish.

I am going to run a set of the ARP2000 studs in a 1500whp motor and see what happens.

 

Sean, is AU7700-2B ARP2000? That was the PN i was given initially but couldn't find them online, only the 1B.

The correct nut for 1B is ARP-300-8308

Plenty of washers available

 

With all of the many part numbers ARP has it makes sense that they had another number that would work on our cars! I really look forward to hearing how this works out as it sounds like it's cheaper and readily available

 

any of you guys have these installed and tested?

 

yes theres a few sets installed

 

Talk to Sean at SillyRabbit, he has multiple cars running these and he gets a bulk discount on them from ARP, he also has a fixture for drilling the holes correctly

 

that would be just for the cases. the heads and cylinder housings have to be machined on a bridgeport or cnc machine

 

I put some in but have not run them. They are huge and I'll guarantee they aren't going to lift on me.

 

Please confirm what torque procedure has been used on these cars running these?

 

Sean at SRM told me to torque them down 10 ft lb at a time each pass, using the factory advised pattern until you finish your last pass at 85 ft lb. So you might start at 15 for your first pass and go from there. I did things a bit differently and used an angle torque after 60 lb ft to finish, I have that info in my build thread.