Vince, you better recheck those prices. The Z28 air cleaner is cheaper --> under $175 w/free shipping.
I'm pretty sure the one Snarfy recommends is smaller in diameter and does not include the lid. I have a Corvette air cleaner here at home and I just measured it --> 15¼" in diameter. And the lid is completely incorrect because it has a rib running around edge where the factory big block horsepower sticker goes.
The 1966 dual snorkel air cleaner is 16½" in diameter, as is the Z28 air cleaner and it has the correct lid, and is a dead-ringer for the 1966 air cleaner.