I think they are using mylar faced foam, or koolmat.com has stuff that is supposed to hold up great to heat, i've never bought or tried it though. I think some of the guys over at WFM use it on their machines.
I'm confused - what foam are we talking about? The only foam part I'm familiar with is the isolation piece on the underside of my hood to direct air in from the intakes in the upper half. Does the 4xx series have foam between the engine and operator as an insulative barrier?