First, thanks to everyone who has commented (Kampala, Rau G, Benz Dr., Lurtch, and Jordan)!
I had my head re-built in 2009 with less than 15,000 miles on it, so I’m hopeful the corrosion bug is not eating away.
As suggested, I did a temperature profile across my radiator and I did find the passenger side of the radiator much cooler than the rest (maybe 30-40 deg.). Just hope my temperature gun reads correctly. Based on this test, my experience of overheating at freeway speeds, and your success with a 3-core radiator, I will move ahead with taking mine to a shop for inspection and testing. It has had nothing done to it in the 35 years I have owned the car.
Further, I am concluding that my fan clutch is not as efficient as it should be. Today, I held the fan stationary until my temperature got to the 212 Deg. F. mark. I released the fan and it did bring the temperature down a few degrees……but not down to 180 Deg F. I then drove the car on the freeway (w/o my A/C going) and the air moving across the radiator brought it down to 180 Deg. F. This is on a 70 Deg. F. day. Granted….. a poor radiator would cause cooling problems at idle too, but I cannot separate the effects from the fan and the radiator. I’ll just replace the fan clutch at the same time. Like the radiator, I believe it is the original.
So far, no one has quantified the benefits of going from a 6-blade to a 9-blade fan. Maybe there is no benefit. I’m still in a quandary as to whether I want to go for the 9-blade fan.
And lastly, I was hoping someone would give me an idea of whether running the timing at 38 Deg. BTDC will cause the engine to run hotter than if the timing is set at say 30-32 Deg. BTDC. If it benefits the cooling aspect, I’m willing to lose a little performance and gas mileage by retarding the timing a few degrees.
Again….. I thank everyone for helping me out.