I've gotta '78 F-150, 300 I6, given to me by my father-in-law. sat up for a few years. when it runs it pours blue smoke and a compression gauge shows it has a bad cylinder. I assumed it needs a ring job but someone told me it could be a stuck valve and pulling the head and investigating that could save me alot of money and time. anyone got any ideas. could it be a stuck valve or what?

 

hook up a vacuum guage and check the reading. surf the net for vacuum guage readings, i had a few saved but all the pages are old and the host expired the pages. dont hook it to the carb, find the vacuum manifold and T into that.

 

If you do a wet compression test on the bad cyl and it improves it would point to rings. A leak down test will tell you for sure and even tell you what valve if it is that.