I like to use an air filter to keep gas from spraying on my crotch. Although, the purpose is to keep debris out of the engine. You will get different opinions from different people. If you can afford one, go ahead and get one.
You probably have the Walbro WD size carburetor. The other popular large carburetor is the Tillotson HD. You can ask around for the original air cleaner or just get a generic unit. Here's an air cleaner that will fit both of those,
After testing to determine if the fan would spin freely, I found a source for the belt on ebay. Received the belt and installed it without any problems. Also salvaged an old air filter from a small dirtbike - just need to drill out two of the three screws on the Walbro carb attached to the Rockwell 440. Should be ready to go after that. Have already cleaned out the tank and reinstalled it.
I noticed that it doesn't have a primer bulb on it so I may put one of those on the gas line to help with getting gas into the carb after it sits a while.
Again, thanks for the advice - I am looking forward to taking this old girl out this winter.