....what kind of truck?? If the engine sits low in the engine compartment where the fan is more on the bottom of the radiator save yourself some grief and put an electric fan on the radiator that will cover the radiator and will pull at least 2200 CFM's. If you can run a standard fan do yourself a favor and put a fan shroud on it. You will not regret doing it now rather than later!
...just my OPINION from my experience.
EDIT: as for how many rows, it depends on the size of the "rows", how close together ect.
Reading this may help you some if you haven't investigated radiators.
http://www.usradiator.com/coresDillion radiator sells "direct bolt in's" for a lot of vehicles. Recently purchased one with the oil cooler in the bottom in case I ever need it, for $200 shipped to my door. I think Champion Cooling, or something like that, actually makes them. Shop around it the best advice.
