Overflow tank

reminds me... I saw a factory resivoir in a E-body that conformed to shape against the right inner fender and bottomed at the frame rail. Looked great ! It sure looked like it would fit my 67 A-body too. The owner wasn't about to let me try it on. Antone have a clue ? (being an e-body part I prolly can't afford 1 anyway LOL)