Here is the scoop. There isn't a brand name for the product. Dad got it from Mac's, a Ford parts dealer in Lockport New York, US.
http://www.macsautoparts.com/ford_mercury_early/
The product is a foil with a thin foam middle layer, maybe 1/4 inch thick. It was glued on the engine cover using a contact cement. The edges were finished with an aluminium duct tape.
Dad thinks there may be similar products at a building supply center here in Canada.