Always difficult to diagnose any Model A we cannot "see".
So often a new Model A owner has no idea if this vintage Model A was left unattended "anytime" during some former past period of time; however, if so, several things can occur when a Model A is left unattended during the past 80+ years.
Others may have lots to suggestions and experiences to add, but from past Model A experiences, a very few damaging things are:
1. The shiny camshaft acquires damaging rust pits on the bottom side when sitting unlubricated, and unattended, and not rotating for years.
2. Unlubricated rings and cylinders standing still can rust in one or more cylinders where they make contact; hence, force is later required to move the piston(s); especially, if the head gasket has a very tiny unnoticeable leak.
3. Points develop oxidation which hampers electrical contact.
4. Valves get stuck with varnish between valve stems and valve guides causing backfire and improper valve timing.
5. Rust forms in gas tanks. and later impedes fuel flow to the combustion chamber which can cause intermittent fuel flow problems.
6. Rodents feast on electrical wires causing shorts or partially disconnected wires reducing electrical power.
7. Rodents can have fun make nests in any open engine connected orifices.
8. Oxidation can occur at several electrical connections thus reducing electrical flow and causing nagging intermittent electrical problems.
9. Unsupervised young kids playing with unattended Model A's can add sand, water, and unknown items to gas tanks and oil pans, plus other unimaginable things that unsupervised kids do to have fun.
10. Just because a Model A runs well when you hand the seller a check does not mean that this vehicle was properly maintained for the past entire 80+ years.
Just hope this helps, when buying a Model A, for one to consider that "all" of the Model A's past history may be unknown.