Take a blow torch and unsolder the seams in the tank and you will find the tank is made of three identical deep drawn steel stampings, saves tooling money, then secondary operations like punching the gas cap hole and forming threads are done, and the slits in the end piece are punched so gas can flow into that extra end soldered onto the tank, and the outlet for the fuel line is punched and a reinforcement plate spot-welded on. I'm pretty sure IH never made gas tanks for Cub Cadets, in fact, Kohler probably bought them and mounted the bracket or saddle and the tank prior to painting, crating, and shipping.
I was soldering/brazing a small crack in the bottom of a tank off a 14 hp Kohler about 20 years ago, I forget why but I had the tank slightly pressurized and eventually I got enough heat into the tank it unsoldered a seam and blew apart, one piece missing my midsection by a small fraction of an inch and then flying 24 ft across my shop.
I won't buy a used tank, you can't see into that section, it could be severely rusted. And new tanks are crazy expensive, think my new plastic 1-1/2 gal tank about 18-19 yrs ago was $40 but the filler neck and cap would have stuck up over the hood about an inch, maybe a bit more. I was able to reduce the height of the filler neck and get a cap with a flat top. I have made 3-4 gas tanks. The one I made for the 72 held a bit over 2 gallons, and had a flush mount fuel cell style fuel filler. I'd like to make a bigger tank for the 70 too using parts off the tank I made for the 72.
