I did a head gasket job last spring, and the heads were shaved a bit to get them flat. Recently, the intake was leaking in the rear and I suspected RTV failure. Much to my surprise, on teardown, it appears the intake gasket did not seal the ports. I've got oil being sucked in to the valve area on both sides, it appears the gasket did not make contact with the head or the manifold on the lower sections of the port openings. The tops of the ports appeared to make contact.
Question: has anyone used RTV on the entire sealing surfaces of both the head and intake, in addition to the factory gasket?? The service manual says don't do it, but unless someone is making oversize (or better quality) intake gaskets, I'm going to have a major problem. Thanks.

 

Shouldn't use RTV on any machined surfaces.

 

Does anyone make replacement gaskets which are thicker?