That may be so while its sitting still. Your problem seems to be happening at speed though. Air does some funny stuff at 70 mph. I can put my hand on my handle bar riser and take all the wind off my face at 70. If my face was a radiator, it would overheat .
OK I'll play with the timing a little and my best bet is probably to put in an al radiator with trans cooling. That will give me better cooling with a better core design plus help with the airflow by getting rid of the tranny cooler. In for a penny, in for a pound!
Here is your set up And here is a ZIPS set up ... The alternator and A/C brackets are cast into the housing ... making for a neat, compact set up. .
You never said what temp it reaches, when throttled up to 1,700 rpm or above..... With the 16# cap, the boil point is raised to about 150 degrees, using a 50/50 coolant / water mix. If it's lower than 260, and stays there,.... it should be ok, barring some other issue. Be sure that cap is holding the 16# it's rated. 4TTRUK
Its easy to check for a partially clogged radiator. Just feel the center of the core with your hand or use a laser temp gun. Radiators tend to clog from the center outwards. If its cold in the center and hotter around the edges.....you have your answer.
I had been having the same issue with my 50 Lincoln (460/c6). I have a dual puller with shroud. Heard from a friend of mine who is into BB Fords that the fan shroud combo is actually blocking too much air coming through the radiator at freeway speed due to the fact that there are only two large holes for the fans. He suggested cutting holes in the shroud where possible to allow air to flow through the radiator. I used an angle grinder with cutoff wheel to cut eight 2 inch holes on top and bottom of fans. The result was 188 going down the fwy instead of 210. I am actually going to pop rivet in some rubber "doors" over the holes so that in traffic, the fans do what they are supposed to do and pull in air over the entire radiator and at speed, the rubber will just blow open.
I got a Champion aluminum radiator from ebay but still overheated so I took the shroud off. Since I am running a single fan it basically has its own shroud. It runs cooler now but still not as cool as I would like. I have replaced the water pump and that helped some more. I am going to install a high flow thermostat and see what that does. Summer is coming and I need the AC.
Make sure that your lower hose has a spring in it or is the type that will not collapse at your higher RPMs. Many people miss this simple fix.
I hear that. The lower hose is a metal 90 elbow with rubber hose clamped at each end. No collapse there. I may pull the thermostat and see what it does without one.