Whatever radiator you fit make sure the rubber mounts are still flexible and have not gone hard. I recall being told the the flex of the Morgan chassis (which is normal) can stress the radiator if it is rigid in its mounts and then it may leak.
Basically, the radiator needs to be stiffly made with thick joints, and mounted flexibly. The flaw with a lot of radiators is the pipe to tank joint. On a normal car, not much strength needed, but on a Morgan - lots! So not only soldered well, but thickly too.
