If it overheated real bad I hope it did not blow a head gasket. And I did have an air pocket in mine once and lost a head gasket. Now I fill it with water and leave pump running for 30 minutes or more. Sometimes I jack up the front of the car to help get the air out of my heads, the radiator is low so I think it is okay. Put a charger on it and let it run and keep topping it off until full. Those little Moroso sewing machine type water pump motors work but they do not move much water so when everything is good no problem but they are marginal and if you have any other issue it makes it worse. With it sitting that long I think you are going to have all kinds of carb problems, trash in the fuel lines. If it was me I would replace every fuel line because they start to come apart putting trash in the jets and or get brittle and will leak which can cause a much larger problem like fire. I would also replace the floats in the carb for same reason. They absorb fuel get heavy then they dump fuel into motor causing a huge fire risk. I would put a NEW filter in line up near the carb to catch any trash. You really do not want fire.
I run a 170* thermostat in my altered but I have drilled some holes so it is always flowing water. If I remember right I drilled 4 holes .125 (1/8') I run the temperature controlled fan sensor and set it at 170*. Most racers do not run a thermostat at all but I do. You can check it to see how it is working by putting it in a pan and boiling it to see when it opens. With the little Moroso pump drive you have that does not move much water I would probably remove it completely if there is one in there at all.
For timing I would leave it as is for now since that guy supposedly had it working good there but in the future I would try lower timing. I think many people run way too much. I am running 28* on my motor now and was told it needs 38* It puts out a little more on dyno at 28* and is easier on starter and rotating assembly to.
I bet the cap and rotor has a bunch of corrosion on inside and those are cheap I would change those out along with plugs and plug wires.
I have drove some cars for other people and I can tell you this I will not drive one with out a diaper. That is one of most important safety devices you can get and they are dirt cheap. Not to save a motor if you blow a motor it is gone but a diaper it can save your life. Many have lost a motor near finish line and wiped out car or got killed. I lost a motor at the finish line back around 2000 and it was a hairy ride and I messed up the whole track but was able to keep it off the walls. They did not have diapers back then for sportsman racers.
