Thanks for the responses.. I have a unknown 6 blade fan and an unknown shroud. It's an automatic and it never boils over and never really runs cooler than 190 no matter the weather. 180 thermostat.
If you have a fan and shroud, an important factor in how well they work together is how much the fan and shroud overlap... You want to have 30% - 70% of the fan in the shroud, the general rule of thumb is 50% of the fan should be inside the shroud...
Also make sure that you have a good seal on the radiator and fan shroud... If there are any gaps, that can be a path for the air to go 'around' the radiator fins instead of 'through' them... You want to funnel as much air into the radiator as possible... The more air that you can funnel into the radiator fins, the more cooling you can get... OEM manufacturers use rubber and foam seals to fill the gaps between the radiator and shroud to keep the air from passing around the radiator instead of through it...
You may want to try going to the home improvement/hardware store and getting some various thickness of foam strips with adhesive and attach the foam to the fan shroud to seal any gaps between the radiator and fan shroud...
Another thing that may cause the engine to run hot is ignition timing.... If the timing is off, that can cause an engine to run hot... Try bumping the timing in 2° intervals at a time to see if it helps it run better and cooler... I would try advancing it first as I've seen cars with timing too far retarded run hot...
