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As to your running hot.

Make sure the timing is set correctly. Start by making sure the arm on the back side of the distributor body travels fully side to side in the slot. If not rectify that first then re-set the timing and see if that stops the overheating.
Are you sure it is actually running hot? Have you checked the water temperature with a thermometer? An inexpensive meat thermometer dipped into the coolant is one of the best ways to actually know what the temperature is.

If re-setting the timing does not correct it...
Check to see that the fins have a good connection to the tubes.
There is not super thick paint on the tubes and fins.
Fan belt is turning the fan. (Do not get it too tight)

If those are good then...
Pull the radiator out and clean it by turning it upside down and back flushing it to get rust flakes that may be sitting on top of the tubes out.
After giving it a good rinsing in all directions plug the bottom tube and the overflow tube. I use a piece of scrap inner tube and a hose clamp for the large outlet and a small piece of dowel or such pushed into the overflow tube to plug it. Put in 1 gallon of undiluted Simple Green in and replace the cap. Invert it several times a day for a few days to a week. This will get the grease and grime out of it. If you had a bunch of rust come out in the initial flush you may need to put in something to dissolve that. Others will have suggestions for that.

While the radiator is out put a garden hose at full bore into the inlet on the side of the engine along with air from your compressor and flush the block out.

All worth a try as a new radiator is pretty spendy.