It not so much a problem of "burning" anything up... the issue is heat transfer to the valve cover, which in turn transfers heat to the oil and the head. A thin sheet of steel, coated with a high temperature insulating material on the header side would work. The insulation blocks the heat from reaching the steel, and what does reach the steel plate will be radiated into the air by the larger surface area, limiting what reaches the valve cover. Won't look very good though, particularly not on something that looks as good as the photos above indicate.

Maybe its overly conservative to even worry about it, but a small collector leak near my oil filter was enough to raise the oil temps.

The dual-cat headers are a major problem. A buddy of mine picked up a set of used AS&M coated dual-cat headers. They came with a full sheet of aluminuized insulation precut for the firewall. We bought some more insulating blanket and coated the heater box. He ran the headers for a couple months, and ripped them off after they melted the rubber and plastic at the end of the dipstick tube/handle, and several other pieces of the engine compartment. I guess that's why AS&M no longer makes the dual-cat stuff.

You should be able to get an aluminum plug made to fill the extra hole in the drivers side cover. Or put a small breather in the hole, and block it off internally so its not functional.

 

A piece of that thermal insulation they have for spark plug wires and boots might fit in there ... ??

 

That looks close enough to fry the valve cover gasket. Like everyone mentioned you should consider insluating the valve cover and/or go with a different header.

-B