Traction woes.

Raced this weekend and 60 ft. times were off. Car is usually pretty consistent. Always hooks and goes straight. Times are always 1.47 to 1.49. This time 1.51 to 1.57 Car is a 70 challenger 3500# 440 and 3800 stall. 3300 s/s springs and no snubber. Ive ran with and without snubber makes no difference. Tires are mt 10.5 29.5 on 9 in. rims. After a race the tires are always pretty smooth. This time they look like someone took a cheese grader to them. Looks like the rubber is peeling off. Just the second race on the new slicks. Buddy said it looked like the car would bounce a little out of the hole. It has never done this before. I am open for suggestions any thoughts would be appreciated.