Is there photos available indicating the 9in housing markings of a Dearborn Sept. built '70 Q code Mach 1?
Catching back up
The problem is that we find similar marks on some rearend and on other examples we find marks that are different or "new" . I've made a practice of only sharing those that appear to be the common, repetitive and documented ones. The others can wait until we find some additional supporting information IMHO
As always its safer not to put any marks that to include marks that should not be there. Consider that others owners may be looking at and coping
the marks on your car - repeating your mistake (if it is incorrect) over and over again. Just a consideration IMHO
The markings that I've seen for a 70 9" rear end housing are as follows - hope this helps
1- The markings on the bottom of the housing (directly below where the 3rd member would mount) are normally seen in white or a yellow. Most of the time these are destroyed by the elements or by floor jacks. Letters are large, applied with what looks like a 1/2" brush and are fairly sloppy. No real pattern as they can include numbers and letters or what looks to be all letters. On many of the housings we see (white or yellow also) a two digit what may be a letter and number on the rear face (back side of where the third member attaches), Not allot of examples so no pattern can be defined at this time
2- Commonly seen is a somewhat small "31" with a line under it to the upper right (looking at the housing straight on from the front) where the center is welded to the drivers side tube. Only seen this done (this year) in white brush or large roller tip painter
3- For your year and application I've also seen the tag or rear axle identifier code written white along the passenger side tube (between the spring clamp location and the center section) on the rear surface of the tube. Example would be 981 The code can be found on the buildsheet or on the rear end tag
4- On a few of 9" 70 rear ends We've found "B' written on the forward face of the rear end housing between where the large u bolts would be placed. Applied in white paint and written upside down from the way the rearend was installed into the car
5- Indicates the blue axle vent and or rear brake junction brake (depending on application one or two locations) mentioned in the thread above
These are the ones I've seen a number of times - as mentioned there are others but those I've only found on individual assemblies and not repeated so far in the research
