You won’t find a reproduction tank for the 61-63 cars. If you do, let us all know. Other than a custom tank (surely expensive) or trying to find a good used one (you never know what you’re going to get, especially if you buy it long distance) you can try to work with your existing tank. There was a topic on this started a while back. Click on the index tab above and then click “discussion topics”…..at the bottom of the first page there is a topic called “In need of new gas tank on 63 olds”. Personally, I’ve tried the do-it-yourself method of coating the tank with with sealer kits like Eastwood’s. I spent quite a bit of time “cleaning” the inside of the tank with the chemicals in the kit along with a length of chain and some buckshot……shook the hell out of it for about an hour, rinsed it and shook for another hour and finally convinced myself that it was as clean as its going to get using this blind method. Well, it worked good for about 4 years then failed at the pinhole that started the whole problem. I know quite a few people who’ve tried this coating method and the coating ultimately peels away from some parts of the tank.
Right now I have a new reproduction tank intended for a 1938-1939 Chevy. It’s a little taller than the original tank but much shorter from front to back, the width is the same and I have no ground clearance issues. It’s secured with new straps, etc. and a fuel resistant rubber hose from the tank to the original filler down-tube. I don’t recommend that anybody else try this due to the potential safety issues. It’s going to work for me until I find a suitable replacement.