It's been my assumption that Fomoco's decision to place the two insulation pads there involved a few factors. Most of the heat would be toward the rear, since air entered via the front thru the radiator, so there wouldn't be a need to cover the front section of the hood, so they placed insulation pads between the center hood support channel and hinge channel at the back. They didn't place a continuous pad all the way across because they believed that insulation above the oil bath air cleaner might somewhat hinder airflow toward the back of the can where most of the air entered the air cleaner, so they left out insulation above the air cleaner. The rising heat does not damage base enamel (on the hood), but I believe that the intention was to have air heated by the engine assist in engine warm-up and once the car started moving, the hot air would pass down the firewall and out under the floor of the car. Another factor might have been to prevent sweating of the hood after the engine was shut off during cold weather.
I did not replace the insulation on either of my '55's after the hoods were stripped down and re-painted. The factory did not paint the underside of the hood on my car very well and when I removed the insulation pads, there were a couple areas of pitted rust underneath. I don't think it hurts anything not to have it.
