So you would say just go with regular intake gasket and put that piece in and call it a day ? I'd rather do it right. I already have oil restrictors in the mains and a windage tray.
Yes. The source of most "milkshaked oil" issues on the 455 Olds and 460 Ford most often can be attributed to the "Bathtub" style intake manifolds gaskets. Stay away from them at all costs. A phone call to Summit racing, or Jeg's can probably net you a replacement for that sheet metal part, if you feel it's necessary.
That being said, I can see it's purpose but is totally unnecessary if you have a windage tray in the pan, oil control mods, and keep the oil at a proper level. Smoothing and deburring the block underneath there would do wonders for oil scavenging to the pan. Also, the Cam is what's directly under there. Hot oil on the underside of the intake manifold would be the least of my worries. Some people with 455's don't have the EGR passages blocked off, which creates 10 times more heat in the intake manifold than the oil can.......

Ray