The Olds likes to keep quite a bit of water in the block, even after pulling the 1/4 npt plugs from the lower sides of the block. I'm not talking about freezing and cracking since you are in AZ but the water there is very alkaline and it will just sit there and rust into a nasty mess. At the least, pull the 1/4" plugs and run some fresh (er) tap water through the engine to flush out the sand and filth. The when it's time to put plugs back in it, use the brass ones or 1/4" ball valves.
Some fuel stabalizer might help to keep your intake valves from sticking when you fire it up in the spring.
Might drain the oil as well.
Some guys like to loosen the valve train to let the springs relax, depends on how particular you are about it.
hmm, what else guys???