My 41 Plymouth is showing signs that there is a lot of under the hood heat that is ot flowing out. The coolant temperature rises on a mid 80's day and the I believe the fuel in the carburetor boils despite the 1/2" wood spacer and the thick black insulator I put under it. This makes for hard starting when the engine is hot. After studying it little, I built it so well that the only air entering the engine compartment is the air being pulled through by the 16" Spal fan and shroud. There is no other entrance of consequence. I have not tried just cutting the fan on at about 180 and letting it run continually but that doesn't seem like a great long term solution. So, the only way is see to increase air flow through the engine compartment is to try to create some negative pressure in it. I am thinking about trying to add a couple of "flaps" below the crossmember to hopefully create negative pressure in the engine compartment and increase flow through the radiator. Anyone else ever tried this or any other method for getting the heat out of the compartment? Next option would be wrapping my ceramic coated headers to keep the heat from them from adding to the heat load. That should help some. Thoughts? Experiences? Last option would be louvers in the hood, I guess but I really don't want to do that. Other options and suggestions are appreciated.