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The way I filled the radiator was to put about a gallon of pure coolant in the engine (cold) and a gallon of water. Then I would start the engine and begin to fill the radiator until it was about an inch above the rows in the radiator. I would keep the engine running until it came up to temperature and fill the radiator with 50/50 mix until it remains at about an inch above the rows then put on the cap. Thanks
How hot does the engine get? Does it actually overheat and boil over? Yes it sounds like a fan/shroud issue. The original radiator would have been a 19" radiator and the HP273 radiator would have been a 22" AC radiator. The aluminum radiator you used should cool it fine with a good fan and/or a shroud.
I probably need to change my name on here. I used to have a 66 Barracuda and that is when I used the 66fish name. I no longer have the Barracuda. But I have named my 66 Dart Clyde. So, I can get in my Dart named Clyde and ride!!
66 Dart, same thing when it comes to radiators and cooling.
I have overheating issues with my 70 Swinger. Yes it actually blow's coolant out all over the place. It has dealer installed A/C but they used the small 19" radiator. Bob at Glen Ray Radiators is going to build me a 22" so the issues should be gone.
The radiator I now use is a 22" radiator. I can't seem to find my receipt so I don't remember the name of the radiator company I got it from. But it is an all aluminum welded radiator that has the exact appearance of the original radiator. It has the rounded tank on top and if it was painted black, unless you was looking for numbers or something it would look exactly like the original. I got the radiator off ebay. It is a 2 row radiator. My brother's 65 dart has the same set up I do and he has no shroud. But he has the original radiator. Although his is a 4 speed. I don't see how that can have anything to do with the overheating. However, I just remembered his has the dual point distributor, this is an ah ha moment for me. Maybe the timing is not right. We did set the total timing to 40 degrees. I wonder if the electronic ignition is not working with the engine properly? I don't know. I'm not a mechanic, my brother is. I was always the mechanic's helper! I understand how much of the mechanics work, but I am no mechanic!
The ignition timing could be part of your issues. Otherwise it sounds like you need more air through the radiator when the car is not moving. I just sold a seven blade fan from a ‘66 273 and it would be interesting to see if just that would have solved your problems. And the auto trans cooler does put some additional heat into the cooling system that a manual trans does not.
I have installed a 7 blade direct drive fan. The air flow through the radiator is much greater now but the same issue is still occurring. The fan is still about an inch and a half away from the radiator. I will do more looking at the timing. I am just stumped!
273 HP auto never runs hot, 1.50 inch between radiator and fan. 300,000 miles