383 Stroker Internal Pressure

Hello --
I had a custom built chevy 383 stroker engine built for my tow rig.
It's an all roller set-up, alum heads etc...
The problem is it leaks oil out the intake - I had several shops work on it - taken the manifold off 5 times, switch to a differnt one, tried gaskets, no gaskets, silicon etc still leaks.
I think its making too much internal pressure - at one time it was blowing oil out the valve cover oil cap - any help to figure out how to tell if its the pressure and how does one eliminate it?
It currently has a PCV and a breather.
Thanks
Stump Puller