You are working on the restoration of your 'big' Austin-Healey, you want to bring the cart (back) to the state in which it once left the factory gates? And then you get stuck on the color of the cooling fin.
He has had to show some color in his life, but what is original now? Only on the 100 / 4, 100 / 6 and 3000 Mk1 was the - cans - cooling fin from the factory (bright) red; after that only (canary) yellow. When dismantling this accessory (...) it is wise to study the state well. From - own - experience - although some forty years ago - it can happen that a leaf breaks off spontaneously. With a giant bang, that part leaves the vehicle via the bonnet ... Back then, let alone nearly forty years later. This is because with strong gas the blades 'bend' and at some point the end is reached. This is called metal fatigue. An aluminum fan was fitted as standard on the 100 / 4. And nothing really happens with that ...