Here's a fix worth trying, before you yank the heads. Get a can of Kroil, made by Kano Laboratories in Nashville, TN, and soak the valve stems from the top by removing the valve covers and squirting the valve stems liberally with the Kroil. Let it sit overnight or longer before starting the engine. Then add about 1/2 pint to the crankcase oil. It can't hurt it, and I've freed up some totally stuck engines by putting Kroil in the cylinders and letting it soak for a few days. It will smell a little funny while it's running, but 500 miles or so of operation, then change the oil and filter, can work wonders with one that's been sitting for a while! Good stuff!
www.kanolabs.com Hmmmm- - - - -
Just looked at their website again, and they've got a specific additive for your problem, "Kreen". It can be used as a gasoline or oil additive to address carbon or rust problems on valve stems, etc. I've never used it, but I have used their products for over 25 years, and haven't found a bad one yet!
Jerry
