Thanks for sending the link, Greg.
In my opinion, the Holley PowerShot is a superior filter to the K&N. It is better constructed and it actually fits the air box.
On the Z28, the K&N is a "universal" filter. It's actually the same filter that is used on a Volkswagon. To make it fit the Z28, K&N makes you use a foam gasket to fill the 1/4 inch gap between the filter and the lid.
The Holley is actually designed to fit my airbox and does not require the gasket.
Also, the Holley is less expensive. K&N was $55, but the Holley was only $34.