It's A Hurricane!
Old Air Products' Hurricane climate-control system is a compact, easy-to-install unit designed to fit most intermediate and compact Fords including Mustang, Falcon, Comet, and Fairlane (depending on model year). To achieve a perfect fit, you'll need to install shims (washers) on the firewall studs to get this unit the right distance from the firewall. Shims will help you achieve rigidity and a solid fit. If you want it close to the firewall, use fewer shims.