What kind of "mileage" do you get with your slicks?

My 65 273 Valiant 4 speed bracket racer was conventionally set up with 8 3/4, 4.56, super stock springs, home fabricated pinion snubber and hooked up well. Until one day, when it suddenly went really squirrely, as if I were racing on water or something. Back in the pit area, i found my 10" M & H slicks had worn down to where the fabric chords were showing. Had a new pair sent out to me right away via Greyhound bus. Must have had way over a hundred runs on the old ones. Maybe 200? I don't know.