Does anyone know of an interchange from another vehicle that I could get a turn signal cancel cam for a 62 Dynamic or Starfire.

 

If there is one, your best bet may be the '62 Chev Impala? You need to look the part up in Hollander's Interchange Manual.

 

It's kinda hard to tell exactly what you need,but I'll try.
The turn signal is cancelled by the action of a roll pin which is driven into the steering wheel. If this is broken it can be replaced by a common 5/32 x 1-5/8 spring type roll pin. This pin acts on the actuator ,which is the part that the lever screws into.This part is listed as #5644991 and is listed as fitting all 1961 and 1962 models with Hydramatic except F-85.
A check of Chevrolet and Pontiac parts books does not show this number so I think the interchange possibilities are slim.