regmudd,
Your '50 came equipped with a 0-30 ohm sending unit that matched the fuel gauge. As you are discovering, these two items need to be compatible or your reading will be bogus.
30 ohm senders are distinctive to the old Chevrolet's. Most vendors have them and the float can be easily bent to function is different tanks. I'm not familiar with 'Yogi', but it doesn't sound like a reproduction style tank.
Stuart
