i do know of one car that had arp's that lasted but what it took to keep that car together far outweighed what it would have cost for a better stud. First they pinned the stud after torqueing them into the block, and then they re-torqued the Head Multiple times. and to do this you must remove the cams to get to the top of the head bolts, and retime the motor after. Book Time as i understand is 33hours to pay for this service once. and multiple times you should have done something different in the first place.

A1 made the studs for BBI, and Evoms up until they went belly up 1-2 years ago. i have A1 12mm studs in my car.

for an 800whp car i dont think 12mm are needed if your not gonna turn it up over 1000whp later. if you truly stay at 800whp. but thats the hard part once you go bigger you tend to want more.

 

its actually even cheaper. we can supply a jig that allows a diy for drilling the case and retapping the new holes. then just the cylinder housing and heads need to be drilled for the larger studs. total time is just a few hrs machine shop time.
the issue isn't really high hp. even at less than 900 hp sean was seeing the 10mm lose torque. its more a matter of do it once with the motor out and forget about them. with any 10mm its is at a minimum a second retorque which requires another engine drop remove the cams and lifters retorque and reinstall everything and new fluids. this additional cost is actually more than what the added cost of the 12mm studs would be. like joe says ONE AND DONE! SRM never pushed me to use them i simply saw the troubles sean had with his and realized the common sense of the bigger studs . 90 ft/lbs wins over 60 ft/lbs every time. no additional cost of having the liners oringed either

 

Was actually thinking 800 at the crank. It's a road car and I don't want to get into gearbox upgrades.

 

the threads of the 10mm studs won't hold that much torque. its a much smaller cross section of force applied to the threads. the 12mm also have more threads per mm than the 10mm

 

its yours to do with what you wish. what we are saying is the arp aren't up to the task. replacing them with another 10mm requires much labor to retorque which in turn costs more money than if you just have the 12mm studs installed. we have seen this in more and more instances. in the end its up to you to decide what works the best for you.

 

If I do mine it's 12mm all the way. No retorque, no O-rings, minimal cost by comparison. The fewer times the motor comes out the happier I'll be. If I understand correctly there's no concern with bore distortion since the sleeves aren't integral. IMO this is a no brainier and good insurance.

 

for what its worth i think what the OP is looking to do can be easily done with good 10mm studs and proper assembly without going to a 12mm stud. i would throw the ARPs in the trash tho.

 

yeah i think he would be better served ditching the 4.0 and keeping it 3.6 and put the money in the 12mm heads studs for what his goals are.

 

what most look at is the cost. 700$ for 10mm studs 1500$ for 12mm studs. factor the r&r to retorque and that difference in cost drops drastically.even 10 hrs r&r at 100$ per hr and your even in terms of cost. at 90 ft/lbs the 12mm aren't coming loose. at 60 ft/lbs the 10mm have started to show a track record of loosening up. maybe not at 800 crank but why take the risk when the solution is right there waiting to be installed?

 

How does anyone in this world validate 1500 for a set of damn studs!

 

custom made in sweden. how is it any more expensive than dropping the motor twice? just look at the size difference, the motor I'm building now (layinbacks 3.8) had both heads lifted with racewear studs. 808 rwhp

 

They are just STUDS!

https://www.extremepsi.com/store/product.php?productid=23258

They can be made and sold very cheap. That price makes zero sense. Even at $700 they are too much but some porsche tax is fine I guess.

 

i wouldn't use arp studs in my lawnmower. but you go ahead and see how they hold up. if they don't then you will have a large reserve of cash for the removal and 2nd rebuild

 

ARP or anyone can build you anything you want. Its not about that but you seem to want to argue and not try to realize that 1500 for a set of studs is highway robbery and that's fine. I never said ARP are good or 10mm are good or anything. I am saying, once again, 1500 for STUDS is just ridiculously priced, period.

 

The problem is the limited market, how many sets will they sell? I agree the pice is steep but I also recall them doing some QA and dumping a bunch of them - these are made right. If they were common or shared anything with another motor they could do volume but I don't think they are. Yes, the price stinks but unless someone can find another quality manufacturer we're stuck with it. I'd be surprised if someone wasn't already looking into it...

Oh, and I bet if you gave them good specs ARP could make them just fine. They do know how to make good hardware IMO.