I believe their original marketing concept was twins without having to do headwork (studs/o-rings).... and with NO egt concerns.
Not sure they expected anyone to push the envelope like many have.... including BD. I was told by someone at BD, they later (3 yrs ago) ran their 24v company truck up to 600 hp with their twins and got good results. with, of course, studs and o-rings.

RJ

 

You're misinterpreting what they've written... they're talking about the break-in/testing phase... on the very next page of the install instructions they give you the instructions on how to adjust the wastegate and they use 55psi as an example... clearly these twins will safely boost well past 52psi... I'm in the same boat as RowJ... I've seen 64psi.... looking for the cash to upgrade to the R700's....

 

can i just do head studs are do i have to do the gasket at the same time.

 

Good question. On 3rd Gens, just doing studs makes a big difference. But 2nd Gens are a whole different animal and the factory gasket is more prone to let go. Obviously, studs would give you added insurance.... but how much, I don't know.
I just don't know anyone that tried it??

RJ

 

I think just studs on 3rd gens hold pretty good with these twins as I understand others that have that combo.

I did just studs for a while on my 24v with my BD twins and my factory gasket held for about a year. It was probably time for a retorque but I believe o-rings is the only way to hold the head on if you are going to fuel heavily with injectors and a pump tap module.

I don't think these are the only twins under this criteria....I'd say all twins on 2nd gens fall under this criteria with injectors and added pump fueling. I know it is trite at this point but if you are going to play, you have to pay.

 

Singles can cause the same issues too, it's not just twins. I had a B-1 that popped the hg at 42 psi.

O-ring is a great way to ensure it holding together, along with 12mm studs. It's the combo that's on my old 97 and holding 58 psi beautifully. I will be doing it to my 95 as soon as I get the tranny in.

FWIW, when I got the head for the 97 done, it was $300 for o-rings and milling of the head, $50 to recess the valves, and $110 for the gasket set and thermostat.