The information below is based on my own personal knowledge and research over time. It may not be 100% correct, so your mileage may vary.
Bowling ball manufacturing plants:
900 Global - San Antonio, Texas
Makers of 900 Global, AMF
Pours for Lane #1, Storm (Tropical line and possibly Hot line)
Brunswick - Reynosa, Mexico
Makers of Brunswick, Viz-A-Ball
Pours for Elite, Morich
Ebonite - Hopkinsville, Kentucky
Makers of Columbia 300, Dynothane (overseas only), Ebonite, Hammer, Track
Pours for Nobody
Lane Masters - Stockton, California
Makers of Lane Masters, Legends
Pours for Nobody
Storm - Brigham City, Utah
Makers of Roto Grip, Storm
Pours for 900 Global (1st batches of original Break), possibly AZO
Tech-Line Products - Spring Lake, Michigan
Makers of Motiv
Pours for Nobody
Visionary - Jennings, Missouri
Makers of Visionary
Pours for Banger
If I left any out or made a mistake, please let me know for my own personal knowledge. Thanks