63 Dart overheating issue

To answer a few of the questions:

Stock pulleys.
Adjusted timing to 2.5 BTDC and adjusted carb to run well with timing setting - no change.
Temp hits about 250-260 and is boiling over.
Water pump pulley is original to car. Don't think it's bigger but didn't measure.

I appreciate the advice on 6 blade fan, fan shroud and other ideas to improve cooling, but I am trying to correct the overheating issue first. Stock everything shouldn't overheat, especially with thermostat eliminated. These cars ran fine like this, so mine should too. Improving the cooling may come later when I decide to start upgrading.

I checked the rad with my thermal gun and found cold spots in the radiator. My best guess is on first start it must have sucked up some debris that never came out of the engine during gasket and seal replacement, or there was an issue during the recore and got some faulty tubes that are blocked. Either way, I am hoping I found the root cause.

Plan is now to pull the rad again and bring it back to the shop that did it to check it again to see if it's plugged or if the tubes are faulty and get it corrected. They are a reputable company so if it was their fault, I'm sure they'll stand behind it and if it was my fault I'm sure they will be reasonable on price to flush it out. Otherwise I will just upgrade to the champion aluminum radiator.