I know its a mustang forum, but I want to know the correct width for a 9' rear to put in 66 fairlane HT, and what ford cars and trucks would be a good source to get one from. I am adding 351 cleveland and C6 tranny to my 66 fairlane.
AFAIK, the only source would be other cars sharing the same chassis, that being '66-'69 Fairlanes and Mercury counterparts. In '68-'69 the Fairlane and Torino had the same body so you can include those models also. Lastly, I believe the '70-'71 Torino will have the same spring perch width, but the body was drastically restyled so the actual width of the rear end housing may have changed also, I don't know for sure. I know for a fact the Fairlane has a much wider spring perch measurement than the Mustang, which eliminates all the Mustang and matching donors for anything that will simply bolt in (I owned a '66 Fairlane myself and remember measuring the rear to compare it to my '73). If cutting and rewelding the spring perches is not an issue then just about any mid to full size Ford/Lincoln/Mercury car from the 70's would be a good candidate.