Hello, I need a '72 AC firewall patch as pictured below. The problem is they normally rust from the inside out due to water held in the heater/AC box to firewall insulation. Hard to see in pix, but you can look right thru mine below the blower opening and several other small spots. Light surface rust OK but no serious pitting please. PM me if you can help me with this and a shipped price to ZIP 14512. Thanks, Glenn