The 1974 Batsford Chess Yearbook (published in 1975) has a few Manitobans listed in tournament results pages.
For the Canadian Open, we see results for 23. John Burstow, 26. Cecil Rosner, 27. Neil Kirton, 169 Scott Cleghorn.
(The seemingly random listing of players after Kirton is odd).
The 1974 Pan-American Championship lists Irwin Lipnowski.