Thanks for all the photos Paul. My IV is plumbed WAY different than your aircraft. A retrofit of that magnitude is out of the question. I saw no signs of leaks but the outlet was plugged solid. My IV has been setting for 10 years! So I opted for the aluminum tank upgrade based on stories like yours. Little did I know that it was designed for the four stroke engine and mounted lower in the airframe. I think I can make it work mounted where the old poly tank was hanging. I'm still toying around with the idea of installing the sump drain in the tank even though access would be tough. It might be useful in the future.

I'm still thinking about how to put a real low point drain where it should be. Right next to the pilot's seat. Not the easiest place, but it is the low point configured as a tail dragger.
Jay