My car came with a huge 6" tall air filter that is definitely the biggest I've ever seen under a hood.
Besides trying to compensate for something it hid my new Holley carb. I looked at getting a shorter filter and then adding a spacer on top of the carb. However, most of the spacers were either plastic and tended to melt or were chunks of aluminum that tended to interfere with the choke linkage. I found somebody on eBay selling a velocity stack air cleaner base that was made of spun aluminum and would raise my filter up about 1.5". That should give me the clearance I want to make my carb more visible. I also picked up a 4" tall reusable filter make by Spectre.
The new filter is half the price of a K&N and also less than half as rigid. It was a little difficult getting it to look circular--one side wanted to push in.
Here's a low shot of the velocity stack base--very nice quality.
Here's a side shot showing how visible the carb is now.