This car originally had AC, so the first panel uses the stock bolt holes from where the AC unit went. It also fills the firewall space where the blower motor used to be.
The second panel is attached with the use of stanchions, so it can be removed and serviced. I will eventually be switching over to the Holley Super Sniper later this Summer, so I dual drilled all of the holes for the different electronics. Makes for an easier transition.