Pretty sure it has to do with how the blades are attached to the center. If all the rivets are tight and pass a visual inspection I wouldn’t be worried at all. The aftermarket rigid “race” 6-blades such as from Derale, Flex-A-Lite aluminum and steel versions are rated to 8000 rpm and that’s not blade rpm, it’s engine rpm. I know Derales have 5 rivets per blade. How many rivets per blade on the Chrysler 7 blade? That’s all I’d be focused on. Tight rivets with no signs of rust around them and run it.
