350 Oil Leak

I have a very big oil leak on my 350. I recently replaced the heads on it and added headers. The leak appears to be coming out in the area of the seam between the intake manifold and the block at the rear of the engine (I used a sealant here to take up the gap when I reinstalled the manifold, did not use the gaskets that come with the set as the supplier advised me not to). It does not leak at an idle but leaks at almost a steady stream when the engine is revved up. It does not leak right after starting, it seems to take about 5 minutes before it begins to leak. I may be wrong but the oil pressure seems to be higher now than before the heads were replaced.

Could the cavity below the intake manifold be getting filled with oil and pressurized to the point where it is blowing out the seal? Is the sending unit in that area and could I be leaking from there? Is there a oil circuit diagram accessable out there?

Any suggestions would be GREATLY appreciated.

Thanks!