This is a unusual National brand valve assembly remover for stuck valves in flathead Ford V8 engines. If you a have ever removed the valves and guides from a flathead Ford, you will understand the need for a tool like this. I have never used this one, but I have used another type that works similarly.
This pressure should drive any stuck guide out of the block, providing you have removed the keeper first. Seems like a good design. I collected flathead Ford tools for years, this is the only one of these I’ve seen.
Let me know if you have any questions.
Rare National F-15 Flathead Ford valve removal tool 32 to 53 V8 Vintage Hot Rod