I had this issue also. I did find a reproduction one for my car (65 Newport) but I have never had good luck with aftermarket or reproductions. I found a place in New York that specializes in restoring them. Cost seems to be reasonable. Quote over the phone sight unseen was 75 to 175 depending on work needed and they will call with a firm number upon their inspection. Place is called Tri Starr Radiator and located in Seneca Falls New York. Website is www.tristarrradiator.com
2 week turn around. I just sent mine in Monday so I can't report results yet.