How long does it take to unlock a flathead V8?

[1950flathead]

My father passed away last year and I inherited a 1950 F1 with a locked up flathead V8. The truck has been indoors with oil and anti-freeze for 30 years, the last time it ran was 18 years ago. I've added about $60 worth of marvel mystery oil down in the plug holes and it's been soaking for about a month now. I've removed the starter and all the belts, but it still won't turn over. Any suggestions on bringing this flathead back to life?