Theres one listed on eBay,
THIS WAS IN THE TRUNK OF A 65 CUDA, IT IS METAL, BOLT HOLES MEASURE 27.5 WIDE BY 9.25 TALL. ROUND HOLE IS 20 INCHES. I DO NOT SEE ANY PART NUMBERS, DONT KNOW IF IT WAS FOR THIS CAR OR NOT BUT IT IS FOR A 22 INCH V8. COULD BE MODIFIED FOR ANY AS IT IS ALL METAL. TOTAL HEIGHT 18.5. TOTAL WIDTH 28.75.2 INCHES THICK. SOLD AS IS NO RETURNS.