I have an Innovate wide band AFR meter that shows my ratios are good (rich on the secondaries). Timing is 16 initial and 38 overall. The pulleys are stock ratio?? The fan is about an inch from the rad. About half of it is outside of the shroud. I just swapped from a 5 blade flex fan to a stock 7 blade flex type fan with no real effect. I do think the 4 core rad was a mistake but live and learn.
Flex blades, even stock ones, are not very good. Factor in years of use and the flex in them is so soft they flatten out too easily. For a $5 experiment, find a fixed pitch, 7 blade stock fan without a clutch at the junkyard and try it. If it is creeping up in traffic, then your not moving enough air through it at low speeds, hence the worn out flex fan thought. If the fixed pitch fan moves enough air to keep it cool, then you can upgrade to a thermostatic clutch fan to keep air flow and reduce parasitic losses. FWIW, dyno testing has shown the factory fixed pitch clutch fan is worth more power than any flex unit, and it does it without compromising temp and speed differences.
Stock pulleys are another compromise. They were designed to cool around 300 gross horsepower and you are way beyond that. While at the yard picking up a fan, check pulley diameters and try to find a larger water pump pulley, or a smaller crank pulley. Driving the pump slower will reduce cavitation and eliminate the potential for air pockets as well as allowing better heat transfer while the water is in the radiator.
The four core was not a mistake. Even a cheap, mexican made unit with thin tubes is going to have 25% more tube area than an old stock two row with thicker tubes. For grins, you can have any radiator shop perform a pressure check on your cap to make sure it is holding pressure at the specified level. If you want extra insurance, ditch the 14# unit and get a Stant Performance 20# cap. That increases the boiling point a fair amount.
