I "believe" that the Speedway brand name faded out around the time WWII started and never came back. Someone else with a better knowledge of older products will stop in to fill in the gaps I am sure
Mark
Don't have any information on Speedway blades but Turtle is probably correct timing wise by looking at the graphics. Very nice display and very unusual to see the entire store display card with 100 blades still intact. See these all the time in individual blades and packs on eBay but not this display. Good luck with finding out more about these.