[Terry, NJ]

Contrary to just about everyone else here, I don't recommend taking the pan down or removing the head. At least not until you get it to run. Taking a head off a model A is fraught with complications(what kind of gaskets? how much do you torque it? how many times do you torque it, How do you get the distributor out, The head is stuck, how do I? .......) These are the complications that make you think twice about owning a Mod. A You're supposed to have fun with this. Ditto for the bottom end Why not start it up and run it for a little bit before disassembling it? There will be time for that later. Start it up on the old oil, run for ten minutes, then change it. You will hear some old timers telling you to use nothing but Non Detergent oil, Yes they still make it. Don't believe it! Run detergent from the start. Most mod. A guys use Shell 15/40. Available from Tractor Supply. I had an engine that was all crapped up with sludge, the oil screen was a bout 80% blocked. The reason for starting on old oil is to give the bearings and cam parts a good scraping before dumping. That rust is Iron Oxide, (FE O2 I Believe ). They make abrasives out of Oxides. When you first start an engine that hasn't been run in twenty five years, you can bet there's plenty of rust. Change again in 50 miles.
Good Luck!
Terry