James,
Google is your friend!
Just to get you started, here's one result:
JEGS Performance Chrome Air Cleaners - Free Shipping on All Orders @ JEGS
There are several "depths" for drop bases for Holley carbs - I use the max for one of my cars.
The hazard in this effort is to check the CFM airflow for whatever filter you end up with - you can strangle a big-block if the filter can't pass enough air. I use a 2-1/2 x 14" diameter filter from K&N that seems marginal, but it fits...
Tom