Like somebody already said, take something like this
MOPAR 400 AIR CLEANER 1973-1974 Plymouth Roadrunner/satellite Dodge Charger | eBay , have Cooter knock the snorkel off, make the hole look like the 340 cleaner and have him poke another hole in the right spot. Refinish it with wrinkle finish and put the pie tin of your choice on it. Most of the lids are the same. The real ones come with a diverter inside to help distribute the air flow. I can get you the dimensions and some pics later if you like. It wont be perfect because the real one has a lip around the hole that would be hard to duplicate but not impossible. You could always line the hole with a black door edge moulding. Might not look TOO bad.