She’s a 1976 model. Double bred King, with dashes of Waggoner studs, Poco Bueno, Roan Hancock, Leo in the mix.
The mare’s sire is Blu’s Wagon Wheel, who is by Blue Glo out of Blonda Dun. Blue Glo is a grandson of the great King. Blonda Dun is by Poco Dun, out of a Sergeant mare. Her dam, Dusty Gray Lady, is by the King grandson Dusty Beaver and out of Lowry Nylon.
If you go to AQHA.com and look up the Hall of Fame, you’ll find stories about King P-234, Poco Bueno, Leo, Joe Hancock. All ancestors of your horse.
Her pedigree is common foundation breeding, I don't see any real standouts closeup in her pedigree. I doubt your horse was intended to be a racehorse, per se. Although back then it was pretty common to try a youngster on the track first (often an unrecorded match track) to see if it had any speed before going on with it to other jobs (show horse or whatever). Since the mare’s pedigree is all foundation stuff, she was probably pretty stocky, and they may have been trying to lighten her up by outcrossing on a TB (I assume that’s what you’re saying your horse’s sire was).
Thoroughbreds intended to be used as QH racehorse sires -- horses like Three Bars, Depth Charge, Beduino, etc -- were hard-muscled sprinters. Not so much Kentucky Derby winners -- the long, lean muscles needed for a 1 mile plus distance race aren't so helpful at 350 yards.
