Just went through this on my car, I have a post on B-Bodies only I thought my alignment was good until I put a straight edge on it now everything seems good. I went through 4 belts usually once they flip I changed them out

71 demon stock stroke 440/indy ez-1 running 10.10 @ 132.14 mph in the 1/4 and 6.36 @ 107.46 mph in the 1/8 not in the same weekend but It did it then I sold it.
67 Belvedere that worked it's way in the 10's