Blue Cardinal never competed in any of the working stock horse type events though did he ? What he won as more at in hand events I'm led to believe.
I mentioned his name to an ASHS die hard once and they laughed at me.
Going by the ASHS studbook the pedigree looks full of either "unknown" or TB breeding. Unknown usually means a station mare or stallion. These horses were usually not regarded as commercial breeding stock but rather as breeding horses for properties ect. They form a part of many stock horse pedigrees. Lots of our greatest mares were station mares that went on to foal a number of Australian Stock Horse impact sires.
The ASHS studbook has a couple of Cardinal progeny stallions registered as SB.
I notice the stallion Cardinal Blue Chip has both top and bottom line inbred to Cardinal.
Blue Cardinal - LOL