I used one of these in my 440 challenger, keeps it 190 degrees all the time.
I also used the same model radiator in my dart with a 408. I did have to take it to a radiator shop and have them move the necks to opposite sides for the small block in the A body, and I opened up the radiator support to allow airflow to entire surface area, fits nicely.
I included a video of a similar radiator, even though the video is for a chebby it shows the radiator core nicely.