The earliest 8.75 in an A-Body that I have heard of would have been the D/Dart in 66. I have never seen or heard of the Valient line being toured with HD equipment.

66 Dart GT, 402 11.18:109 Best 63 1/2 Galaxie 500XL 406 4Speed 13.20:103 Best 2000 Ram 2005 Durango Hemi.