Originally Posted by Tony Mannock

the crankcase pressure you refer to is equal no matter where you stick your fittings
The engine is merely an odd complex shaped container. Try to picture your engine as a simple container.
If you have pressure in your crankcase your engine is either fooked or your breather is crap and cannot flow sufficient gases.
your crankcase pressure should be no more than 1 atmosphere or to the layman 0
ideally some negative pressure is preferable which is what a new standard cosworth had with it's breather design on engine decel

Originally Posted by Tony Mannock

a simple fix to the ggr and spec r systems is to convert your catch tank into a separator. This is quite simple you need to modify the catch tank by fitting a -10 fitting and pipe to the lower most point of the tank ie convert the drain tap /drain blank.throw the tap /blank in the bin.

Pipe this new -10 fitting back to the convenient crankcase fitting on the block by the block coolant drain plug. you will need to heat wrap the pipe and also make sure it has constant fall and is routed clear of the exhaust and manifold
If you are already using this point on the block you will need to T into it making sure the priority flow is from the catch tank.
IF using a ggr catch tank you will need to add a second -10 min fitting on the upper most corner of the tank to atmosphere.
The spec r catch tank does not require this as it has huge atmospheric flow just pore crankcase flow.
By carrying out the above modification you have also increased the crankcase flow.
I hope the above is easy to understand
you have now converted your breather system to the Turbo systems design of the 80's era