I "think", if I recall correctly those rear ends are within three quarters of an inch a lot of people use the three and a half inch or 4-in backspacing
Mine is a 68 -70 housing and the 66-67 are a wee bit narrower, Spring perches I cant remember off the top of my head but should be close for an A-body. If not just move them. All of this is in a sticky some where.
