Good morning to everyone!
I am working on a project in my fiat coupe with stilo 2400 engine with a big precision turbo for 800hp and i was wondering what head studs should i use to handle so much pressure. There are very long and ARP dont have that size to send me. Are Fiat head bolts so strong to put them?Has anyone used another brand to help me because i dont know what to do. Thanks for advanced!

Try talking to johnnybravoturbo on here. He has a high Bhp coupe.

You could use 2.4JTD head bolts. They are M12 and shorter than original. But you must use torque plate with this option as these bolts will make more distorsion to the cylinder than original ones.
Also don't tap the thread from start/top of the block. Leave it "blank" for first cc 10mm. This will reduce stress to the top of the block.

I was searching a lot for this subject, and ARP's M10 custom age bolts are not "stronger" than original M12 from 2.4JTD. Only advantage in ARP's are stud and nut sistem that is more reliable to tighten properly. But M12 ARP's will be bullet proof
ARP could make custom studs, no problem. But the price of these studts make them not profitable.

m12 will mean block work. Ive gone for m10 head stud kit and il run until the head lifts but i think the bores will crack before then especially at the bhp your aiming for.

as for JBT's lump if i remember rightly he is running Darton sleeves to cope but i maybe wrong

I used these:

Peugeot M12
http://www.ebay.de/itm/Zylinderkopfschraube-Satz-Zylinderkopfschrauben-Satz-M12-RENAULT-47857-/381541750863?fits=Make%3APeugeot&hash=item58d5a9184f:g:jKAAAOSwezVWucui
Are as long as original. I tightened these headbolts to 95NM, about 15NM stronger than original. No Problem so far...
Juergen

im using m12 jtd bolts on 16v and this is better than arp and much cheaper

I had a talk about uprated head bolts / studs on french fiat coupe forum (about 16V turbo engine as they are more prone to head gasket problems)...M12 are not always better than M10 from ARP, there are a few parameters that can modify the resulting preload.

I regularly run 1.8 bar on standard bolts without any issues.

Unless you Running 2.5 bar or above I don't see it being an issue.

thank to all of you!!i will run with standard bolts and we will see!