The internet archive has tons of old radio shows too; my favourite is The Adventures of Sherlock Holmes, which aired in the early 40s. Best thing is that it also has the original ads in there. “Now that the poultry shortage is over, why not enjoy a glass of wine with your Sunday chicken roast?”

Might be cute to include some old original programming in your pirate radio!

https://archive.org/details/sherlock-holmes-1939-11-06-6-the...