hi i am looking to build a turbo motor. is it recomender to oring the heads/block or is that the old way and they do something different now? like just a steel shim gasket? and it is a 2 bolt 400 should i look into splaying the main caps please give me some info.

 

o-ringing works, but that just makes something else the weak point, like the pistons. There are also Felpro and other gaskets that have lockwires in them already and you just machine the heads for the groove and use those gaskets, though for most people this is way overkill and unnecessarily unless you’re running big boost/power numbers…

 

Go with a set of titans, I've used permatorqe felpros on my buick before. I'll be using the titans on the V8....

 

what boost levels make it a must for O ringing the block , etc.

 

Boost v/s CFM is tricky. You may see 25psi on a small head and tpi setup whereas just by switching to a miniram type and removing that restriction the boost will go down a few psi. For anyone to tell you what boost level requires o-ringing would be speculation.

It's all about airflow, if you could remove the main restrictions in the intake you'll see less boost, but will flow more useable air at a lower air charge.

With head designs like a standard sbc the extra bolt holding each cylinder head down goes a long way. On fords, the new LS series and turbo buick engines the limiting factor is clamping force holding the heads on. They have 4 bolts around each cylinder.

You also have to take into account that if the heads do not lift that pressure is gonna find a way out(usually through your block or oil pan). Using a properly surfaced deck with those SCE Titans and arp studs should hold without a problem for all but the most insane numbers.

 

The better felpro composition head gasket should hold you for most applications. They are right the 5 bolt per cylinder setup is one of the best for holding pressure down. The way that I see it is, if you machined the motor and heads true and flat there should be no problem with composition even for higher levels of "boost" (subjective to how much it can take in). When they go it is usually for the best if the machine work was correct.

 

I ran 15psi out of a roots for several years on the felpros with no problems.