St. Catharines Propulsion Plant is a General Motors Canada engine and manual transmission factory in St. Catharines, Ontario.

Opened in 1954 and located on Glendale Avenue.

The factory supports production of cast engine blocks from Defiance Foundry in Defiance, Ohio and Saginaw Metal Casting Operations in Saginaw, Michigan.

Starting in 2012, it also produces GM's new six-speed transmissions.

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