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so since it runs cool at speed but heats up to 230 in traffic I believe we have an air flow problem not a coolant flow problem.
Yes. Many stock Panteras did this from Day 1; Ford tried to fix this without spending any money- moving the sender to the surge tank 4 ft away from the heat source, adding two different resistors, and finally, changing to a 0-260F gauge with a built-in resistor after using up all the 0-230 gauges. All the late gauge actually does is not appear to be pegged. 230F is not particularly hot; my wife's '97 Z-28 has a single rad fan that doesn't even turn on until 230F. 'Hot' is 260F and above using a 16-lb rad cap. If your overflow tank is not spitting up, the engine is not overheated.
If the 351C bypass channel is blocked with an aftermarket waterpump or a 3/4" freeze plug in the brass washer, removing the thermostat will usually radically drop engine temps. There was a GT-5 at an open track event a few years ago that never got to 160F in many, many hard laps with an ambient temp of 98F. Around Las Vegas in the summer, the engine ran at 140F- too low to get heat out of the heater in winter or defrost the windshield. The owner didn't know the engine had no thermostat until I worked on it. After adding the proper unit, the engine temp immediately jumped to an average of 200F on a 900 mile cruise. And he could finally dispose of that dirty wipe-rag he used in place of a defroster.
If the bypass channel is NOT blocked, the engine WILL overheat at low speeds, assuming a marginal stock radiator and stock fans. The bypass channel ID is about 6% of the water pipe ID to the rad, so 6% of the boiling hot water from the engine will never make it to the radiator. Couple that to a stock rad that's 20% smaller than a Corvette rad (same size & power V-8 engines), add in too-small fans, and you have an overheating 351C. Once you get going above about 30 mph, the 'overheating' goes to sleep but adding 30-mph fans fixes the problem at all speeds. There are other factors, but this seems to be the main one IMHO.