Here is what I did when I got my Iron Duke, after setting for ten tears in a barn. The first time you try to start it, most likely one or two of the push rods will bend. That will make it miss for sure. There a real bear to get out once they bend, like trying to stuff tens pounds of poop in a five pound bag. LOL. I had to remove the valve cover and used brake clean on the valve stems, a brass punch, and a hammer to get the stuck valves loose, once they were loose, I put a can, (the whole can) of Sea Foam in and left it in for about three to four hours, at a high idle and some short trips around the block. Changed the oil and put a smaller amount of Sea Foam in it. Ran like a new car then.
Those push rods are hard to come by, my local NAPA had them in stock, surprised me, they can get them though.
Good luck, NICE car!!