Fumblin, you want to stay with a lighter oil on that 216 if it's in good shape. The later motors can take the heavier stuff, but the 216 likes it thin. With the oiling system of the 216, you want it flowing good right away. This discussion has been around a long time, but I've used a quality 10W30 in mine for years with no problems. Just keep it clean and full.
If you've just got this truck running, you may want to consider dropping the pan and cleaning out all the sludge in the bottom. It's easy to do and will give you a little piece of mind.
