AJ/FormS said

I would never tell you to cut a hole in your hood and seal it to the carb. But if you do cut a hole in your hood, seal it to the carb.
My IR gun says that headers idle in the 300 to 500 Degree range right at the flange. My aluminum heads run a tic over 205,and so does the top of my rad. There is no other way for the hot air to escape from under my hood except down. So the 205* plus air from the rad flows over the hot heads and down over the really hot headports, down the hot tubes over the relatively cooler oil filter and P/S box,and out the bottom. I have no idea of the exit temperature, but I bet you could burn marshmallows in a heartbeat! Of course heat rises, so heat is trying to cook the carb. I have a 68 hood with those neat-O metal hood dress-ups. I elevated them with spacers, and cut a bunch of exhaust ports under them, fitting them around the hood bracing. With the car stopped you can really feel the heat coming outta there.
Ram air boxes are available to bring fresh air in from behind the headlights, but they are pricey. I was too broke for that, I'm always too broke. I had a spare factory hood, so out came the jigsaw!

Click to expand...