327 intake manifold

Hi I am new to this forum and have one question hopefully you guys can answer. I installed a polished edelbrock intake and new valve covers on a 327. The stock intake was the type with the oil fill tube on it. Does this do anything else besides being used to fill the engine with oil? The gaskets are being pushed out of the front and rear of intake between block and manifold. Is there to much pressure inside the block? I know now not to use gaskets and just use a good silicone. I have been told this oil fill tube was also a vent for the crankcase. I have vents on the new valve covers. Will this suffice? Or do I need to put a manifold with the fill tube on it for venting purposes. Any help would be greatly appreciated. I am trying to get my 66 Chevy pickup back on the road. Thanks.