Leonard Starr credit from Jerry Bails' Who's Who.
Flash is the Hooded Horseman's dog.
Pencils previously credited to "same guy who did DCs Bomba #1??"
GCD Mail page suggests this to be art by McCarty, and the faces and horses compare well with signed or credited work on "Kid Colt Outlaw" #50 (Atlas) and in "Black Magic" #16 (Prize). He is not found in Jerry Bails' Who's Who. The inker is not certain.