By 1943, it was clear that the Canadian Ram tank could not keep up with the Sherman. The AFV Users Committee of the First Canadian Army was willing to switch to the Sherman, but their requirements were clear.
Now, let's compare the Canadians' predictions to actual engine reliability.
The lauded GM diesel engine didn't do too well. Out of the four engines submitted to the 400 hour/4000 mile endurance trials, only one made it to the end. Of the Ford engines, none survived. The Wright engines, the begrudging third choice, actually performed the worst of the bunch. The complaining about the Chrysler Multibank did not seem to be deserved: two engines completed the test successfully, with one more still in the running.