I think that should have read 848 not 948. The original basic Mini (including the one I bought new in 1968, my first car) had an 848 cc engine. With a good tail-wind it would reach 70 mph, but of course it handled so much better than most other cars on the road so although you couldn't go fast, you didn't need to slow down for corners!
Ken G, 1925 Rover 16/50 (San Francisco)