Another question I have is if ARP studs necessary? I mean, what do they do in fact? I see it like they are harder to deform because of stress and heat, but is this deformation significant?

From what I know of material deformation, stock studs should be fine, but for personal information I'll try to calculate deformation of each studs depending of the pressure in cylinder and where they are located on the head. Should be an approximation but should give a good idea of what's going on with this...

Rod bolt would be harder to calculate but I can try

Remind me good moments in my mechanical engineering studies... Btw, on the last smiley it say "lips sealed" but I tought they were "will puke"...

 

no this is the puke smiley

 

LOL yeah, this one looks better!

 

I've had quite a few friends who have had blown headgaskets from using the OEM head studs. After upgrading to ARPs, but one friend is making almost 600hp if I remember correctly, with a ported/upgraded LS head and a big turbo. I wish I still had that evans tuning dyno graph that was his, but he did that at least 2-3 years ago.

I've also seen first hand a few spun rod bearings. I think the ARPs are good insurance considering how small the OEM bolts are and how much abuse they take. That being said, there is an Epic Tuning hatch that made well over 400 hp on stock d-series rods/bearings/bolts and never stretched a single bolt....instead they bent all the rods!

This being said, I think as long as you have a very good tune, stock bolts should last a long time. But at the same time, I think you could get a cheaper tune with some beefier parts, and pay less in the end.