Any 8.8" rearend out of a Fox Mustang will "bolt in." That being said, I don't think Fox Mustangs had 8.8" rears until '85 or '86. IIRC, the brake lines are routed differently so you'll need to work that out as well. Additionally, 8.8" rears out of Fox Thunderbirds or SN-95's should bolt in but...