Feel free to object if you know something I don't, but when I helped a friend get a Dodge Power Wagon (340ci I believe) based RV going a while back, we added a bit of oil to the cylinders to help make sure the rings were free before hand-cranking and eventually starting it. I think it was an upper-cylinder lubricant, or we may have used motorcycle oil/gear oil of some sort. The RV hadn't run in 3-4 years if I remember right. I can't imagine this causing problem, but if you don't feel comfortable trying that, don't do it