Idle, Idle Surge, Timing Adjustment and heat...

[asshanson]

Having base timing not at exactly 5* btdc will not cause your overheating issue. Also I disagree with your theory that not having a thermostat will cause the overheating, it's not going to heat soak the radiator. No thermostat is the coldest your car is going to run, and it's not really good to run without one.

Get a stock fan with shroud and install that. The little single slim fan probably isn't flowing enough air at low speeds. I know my single slim fan did nothing compared to my stock one.