I have a 29 Model A PU, we have been having overhe
The most common problem if the engine overheats quickly is that the timing is too retarded. Have you seen the exhaust manifold turn red? Extreme timing problems will cause this to happen.You are advancing the timing lever on the steering column once you have it started?
The Model A runs pretty cool if everthing is up to par. The water pump should not be a key to the answer. The Model A pump is really too efficient. It was designed to keep the engine cool while traveling down a dirt road @ 25 mph. At modern highway speeds 40-45 mph the rad cannot handle the volumne of coolant that is pumped into the rad. It will overflow & throw coolant out. Once the coolant is low the engine will then overheat.
Have you checked the cooling system for bubbles that might indicate a blown head gasket or crack in the engine?
This should not be a major problem to cure once you find the problem. You will be able to enjoy your Model A once you get this behind you.
Hope this helps!