the old Pop Photo (and I recall Modern too) had a tolerance of +- 25% to 1/250, and +- 35% 1/500 and over. They also showed pre and post torture test results, as well as error caused by extreme temperature.
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PopPhoto - Digital camera reviews, digital SLR Tests, photography news and all things digital imaging. search for 'featured used camera' and there's a list of vintage reviews. Many good brand / model cameras had shutters that were off the tolerance at highest speeds.
The only Pentax, the Spottie F, was well within tolerance. The Nikkormat FT2 was something like 70% fast at 1000 after torture. The Nikon FM and Leica R3 were well within tolerance. Canon F1 was just at the tolerance border at 1000, and 50% slow at 2000. (heh heh)
In MF, for example, the Bronica SQA was a bit more than 45% slow at 500.